Cannabis Use, Cognitive Change, Adolescent Behavior
Conditions
Brief summary
This study will use a randomized controlled design to test whether 30 days of cannabis abstinence, compared to 30 days of monitoring, is associated with improvements in cognitive functioning. Non-using controls will also be enrolled to determine the clinical significance of any cognitive improvements with abstinence.
Detailed description
This is a 5-year randomized, longitudinal trial of cannabis abstinence designed to determine (1) if performance improves with abstinence beyond that observed with continued cannabis use, and if so, (2) when during abstinence cognitive improvement occurs, and (3) whether performance in abstinent individuals returns to performance levels observed in non-using peers. We hypothesized that abstinent adolescent cannabis users would have more neurocognitive improvement over four weeks compared to non-abstinent cannabis users, and performance would continuously improve throughout four weeks of abstinence. We will recruit 210 adolescents with and without regular cannabis use. Eligible cannabis users will be randomized to either a contingency management intervention which will incentivize 4 weeks of cannabis abstinence (n = 70), or non-contingent monitoring with no abstinence requirement (n = 70). All participants (including non-users; n = 70) will complete cognitive assessments, toxicology testing, self-report questionnaires and semi-structured mood and substance use interviews during the 4-week study as well as one 30-day follow-up visit. Abstinence will be indexed by decreasing levels of cannabis metabolites in urine.
Interventions
BEHAVIORALAbstinence
Cannabis users randomized to this condition will be enrolled in a contingency management intervention for 30 days of cannabis abstinence.
Sponsors
Massachusetts General Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
NONE
Intervention model description
Cannabis users are randomized either to 30 days of cannabis abstinence or 30 days of monitoring with no abstinence requirement. Non-users are not randomized.
Eligibility
Sex/Gender
ALL
Age
10 Years to 19 Years
Healthy volunteers
Yes
Inclusion criteria
General Inclusion Criteria for School-Aged Study Component: * Male and female adolescents from the Boston area who are between the ages of 10 and 19 (inclusive); * Have a parent or legal guardian who is able and willing to provide written informed consent for the active study phase (if under the age of 18); * Competent and willing to provide written informed assent for the active study phase (if under the age of 18); * Competent and able to provide written informed consent (if age 18 or older) * Able to communicate in English language * Able to commit to 9 study visits in approximately 60 days * No severe developmental delays (including, but not limited to, Autism Spectrum Disorder, Intellectual Disability, and Down Syndrome) * Able to safely participate in the protocol and appropriate for outpatient level of care Cannabis-Using Group Inclusion Criteria: * Use of cannabis at least once per week on most weeks * Cannabis use reported within 7 days of both baseline visits * No immediate plan to discontinue cannabis use Non-Using Group Inclusion Criteria: * Use of cannabis less than 5 times in lifetime * No cannabis use in the past year * No cannabis use before age 16
Exclusion criteria
for School-Aged Study Component \- Passive consent for initial school-wide assessment withdrawn by parent or legal guardian or written parental consent not provided prior to screening
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Mean Difference in the Participant's Strategy for 6-8 Box Conditions From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The number of times subjects began a new search from the same box they started on in previous trials. It is assumed that a person who begins from the same box each time is using a planned strategy to find the tokens. This is a specific measure from the Spatial Working Memory (SWM) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SWM module provides a measure of strategy as well as working memory errors. Count variable, ranging from 2 to 14, with higher scores indicating low strategy, meaning a subject began searches from many different boxes. |
| Mean Difference in Stop Signal Reaction Time From Stop Signal Task (SST) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The estimate of the duration at which a person can successfully inhibit a response 50% of the time, represents the time before which all actions become ballistic and a subject is unable to cancel a response selection. This is a specific measure from the Stop Signal Task (SST) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SST module assesses response inhibition (impulse control). Response time variable in milliseconds (ms), ranging from 0 to 500 ms, with higher values indicating that it takes longer for a person to inhibit a response. |
| Mean Difference in the Total Number of Between Errors From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The number of times a subject incorrectly revisited a box that had contained a token in a previous trial across the 4, 6, and 8 box conditions. This is a specific measure from the Spatial Working Memory (SWM) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SWM module provides a measure of strategy as well as working memory errors. Count variable, ranging from 0 to 63, with higher scores indicating worse performance. |
| Mean Difference in the Total Number of Errors From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The number of times the subject chose the incorrect box for a stimulus on assessment problems plus an adjustment for the estimated number of errors they would have made on any problems/attempts/recalls they did not reach. This is a specific measure from the Paired Associates Learning (PAL) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The PAL module assesses visual memory and new learning. Count variable, ranging from 0 to 70, where higher scores indicate more errors and worse performance. |
| Mean Difference in First Attempt Memory Score From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The number of times a subject chose the correct box on their first attempt when recalling pattern locations, which was calculated across all trials. This is a specific measure from the Paired Associates Learning (PAL) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The PAL module assesses visual memory and new learning. Count variable, ranging from 0 to 20, where higher scores indicate better memory performance. |
| Mean Difference in Forward Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The longest length of sequences (spans) a subject successfully remembered in the original order. This is a specific measure from the Spatial Span (SSP) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SSP assesses visuospatial working memory capacity. Count variable, ranging from 2 to 9, with higher scores indicating better memory performance. |
| Mean Difference in Reverse Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The longest length of sequences (spans) a subject successfully remembered in the reverse order. This is a specific measure from the Spatial Span (SSP) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SSP assesses visuospatial working memory capacity. Count variable, ranging from 2 to 9, with higher scores indicating better memory performance. |
| Mean Difference in the Total Number Correct in the Immediate Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The total number of distinct words a subject correctly recalled from the studied list of 18 words during the immediate free recall phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 18, with higher scores indicating better immediate recall performance. |
| Mean Difference in the Total Number Correct in the Delayed Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The total number of distinct words a subject correctly recalled from the studied list of 18 words during the delayed free recall phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 18, with higher scores indicating better immediate recall performance. |
| Mean Difference in the Total Number Correct in the Immediate Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The total number of words a subject correctly identified as either previously studied or novel during the immediate recognition phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 36, with higher scores indicating better recognition memory performance. |
| Mean Difference in the Total Number Correct in the Delayed Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The total number of words a subject correctly identified as either previously studied or novel during the delayed recognition phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 36, with higher scores indicating better recognition memory performance. |
| Mean Difference in the Total Number Incorrect From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The total number of words a subject correctly identified as either previously studied or novel during the delayed recognition phase. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Count variable, ranging from 0 to 160, with higher scores indicating more errors and worse performance. |
| Mean Difference in the Response Latency From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The response latency for each participant was defined as a summary (median) computed over their response times for all correct responses irrespective of condition. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Response time variable in milliseconds (ms), ranging from 100 to 2000 ms, with higher values indicating slower performance across all trials. |
| Mean Difference in the Incongruency Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The incongruency cost for each participant was defined as a summary (median) of response times for incongruent trials minus a summary (median) of response times for congruent trials. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Difference score in milliseconds (ms), ranging from -1900 to 1900 ms, with higher values indicating slower responses on incongruent trials, suggesting that it takes longer to process conflicting information. |
| Mean Difference in the Multitasking Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The multitasking cost for each participant was defined as a summary (median) of response times for the multi-task blocks (trials alternated between having to respond to the direction or position of the arrow) minus a summary (median) of response times for the single-task blocks (all trials consisted of either responding to the direction or position of the arrow). This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Difference score in milliseconds (ms), ranging from -1900 to 1900 ms, with higher values indicating slower responses on multi-task blocks, suggesting that it takes longer to process multiple sources of information. |
| Mean Difference in Number of Problems Correctly Solved on the First Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The total number of trials where the subject chose the correct answer on the first attempt. This is a specific measure from the One Touch Stockings of Cambridge (OTS) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The OTS module assesses executive function based upon the Tower of Hanoi test. Count variable, ranging from 0 to 15, with higher scores indicating better performance. |
| Mean Difference in the Latency to First Correct Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The latency to first correct choice for each participant was defined as a summary (median) of the response times for all trials in which the subject picked the correct choice on the first attempt. This is a specific measure from the One Touch Stockings of Cambridge (OTS) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The OTS module assesses executive function based upon the Tower of Hanoi test. Response time variable in milliseconds (ms), a positive unbounded variable, with higher values indicating slower performance across correct trials. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Mean Difference in the Reponse Latency for Hits From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | The response latency for hits for each participant was defined as a summary (median) over the set of response times for all correct responses (identification of target 3-digit sequences). This is a specific measure from the Rapid Visual Information Processing (RVP) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The RVP module assesses sustained attention. Response time variable in milliseconds (ms), ranging from 100 to 1900 ms, with higher values indicating slower performance in detecting targets. |
| Mean Difference in the Measure of Discriminability - A' From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4 | 1, 2, 3, and 4 Weeks | A transformation of the proportion of hits and false alarms, providing an estimate of a subject's ability to detect the target sequences of digits after controlling for response bias (i.e., biases to respond or not respond irrespective of the stimuli on screen). This is a specific measure from the Rapid Visual Information Processing (RVP) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The RVP module assesses sustained attention. Bounded continuous variable, ranging from 0 to 1, where higher scores indicate a greater ability to discriminate between targets and distractors. |
Countries
United States
Participant flow
Recruitment details
Recruitment was conducted from 2017 to 2022.
Participants by arm
| Arm | Count |
|---|---|
| Abstinent This group of cannabis users are agree to remain abstinent from cannabis use for 30 days.
Abstinence: Cannabis users randomized to this condition will be enrolled in a contingency management intervention for 30 days of cannabis abstinence. | 54 |
| Monitoring This group of cannabis users are not asked to change their cannabis use behavior. | 66 |
| Non-Users This is a group of adolescents with little to no cannabis use history and is non-randomized. | 69 |
| Total | 189 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 |
|---|---|---|---|---|
| Overall Study | Did not abstain from cannabis as per protocol | 4 | 0 | 0 |
| Overall Study | Lost to Follow-up | 6 | 2 | 0 |
Baseline characteristics
| Characteristic | Monitoring | Total | Abstinent | Non-Users |
|---|---|---|---|---|
| Age, Continuous | 18.1 years STANDARD_DEVIATION 1.5 | 17.8 years STANDARD_DEVIATION 1.7 | 18.3 years STANDARD_DEVIATION 1.4 | 17.0 years STANDARD_DEVIATION 1.8 |
| APSS | 0.3 Score on a scale STANDARD_DEVIATION 0.8 | 0.2 Score on a scale STANDARD_DEVIATION 0.7 | 0.1 Score on a scale STANDARD_DEVIATION 0.6 | 0.1 Score on a scale STANDARD_DEVIATION 0.5 |
| AUDIT | 5.9 Score on a scale STANDARD_DEVIATION 5 | 4.3 Score on a scale STANDARD_DEVIATION 4.6 | 5.4 Score on a scale STANDARD_DEVIATION 4.8 | 1.9 Score on a scale STANDARD_DEVIATION 2.5 |
| CUDIT-R | 14.1 Score on a scale STANDARD_DEVIATION 5.5 | 13.9 Score on a scale STANDARD_DEVIATION 5.4 | 13.7 Score on a scale STANDARD_DEVIATION 5.4 | 0 Score on a scale STANDARD_DEVIATION 0 |
| Days Per Month Spent Drinking Alcohol | 0.4 days STANDARD_DEVIATION 0.8 | 0.4 days STANDARD_DEVIATION 0.7 | 0.7 days STANDARD_DEVIATION 0.8 | 0.1 days STANDARD_DEVIATION 0.2 |
| Days Per Month Spent Using Cannabis | 3.3 days STANDARD_DEVIATION 2.6 | 3.5 days STANDARD_DEVIATION 2.7 | 3.6 days STANDARD_DEVIATION 2.8 | 0 days STANDARD_DEVIATION 0 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 16 Participants | 30 Participants | 5 Participants | 9 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 50 Participants | 159 Participants | 49 Participants | 60 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| PQB | 3.8 Score on a scale STANDARD_DEVIATION 3.8 | 2.8 Score on a scale STANDARD_DEVIATION 3.4 | 2.9 Score on a scale STANDARD_DEVIATION 3.7 | 1.8 Score on a scale STANDARD_DEVIATION 2.3 |
| Race (NIH/OMB) American Indian or Alaska Native | 1 Participants | 2 Participants | 1 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 7 Participants | 17 Participants | 4 Participants | 6 Participants |
| Race (NIH/OMB) Black or African American | 10 Participants | 34 Participants | 10 Participants | 14 Participants |
| Race (NIH/OMB) More than one race | 11 Participants | 21 Participants | 6 Participants | 4 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 3 Participants | 11 Participants | 2 Participants | 6 Participants |
| Race (NIH/OMB) White | 34 Participants | 104 Participants | 31 Participants | 39 Participants |
| Region of Enrollment United States | 66 participants | 189 participants | 54 participants | 69 participants |
| Sex: Female, Male Female | 31 Participants | 97 Participants | 26 Participants | 40 Participants |
| Sex: Female, Male Male | 35 Participants | 92 Participants | 28 Participants | 29 Participants |
| THC-COOH | 389.6 ng/mL STANDARD_DEVIATION 745 | 306.3 ng/mL STANDARD_DEVIATION 594.6 | 211.8 ng/mL STANDARD_DEVIATION 338 | 0 ng/mL STANDARD_DEVIATION 0 |
| Years Spent Using Cannabis | 3.4 years STANDARD_DEVIATION 1.5 | 3.4 years STANDARD_DEVIATION 1.4 | 3.3 years STANDARD_DEVIATION 1.3 | 0 years STANDARD_DEVIATION 0 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 54 | 0 / 66 | 0 / 69 |
| other Total, other adverse events | 49 / 54 | 46 / 66 | 31 / 69 |
| serious Total, serious adverse events | 0 / 54 | 0 / 66 | 0 / 69 |
Outcome results
Primary
Mean Difference in First Attempt Memory Score From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4
The number of times a subject chose the correct box on their first attempt when recalling pattern locations, which was calculated across all trials. This is a specific measure from the Paired Associates Learning (PAL) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The PAL module assesses visual memory and new learning. Count variable, ranging from 0 to 20, where higher scores indicate better memory performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in First Attempt Memory Score From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4 | 16.2 score on a scale | Standard Deviation 3.2 |
| Monitoring | Mean Difference in First Attempt Memory Score From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4 | 15.8 score on a scale | Standard Deviation 3.4 |
| Non-Users | Mean Difference in First Attempt Memory Score From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4 | 16.1 score on a scale | Standard Deviation 3.6 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.495Mixed Models Analysis
Primary
Mean Difference in Forward Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4
The longest length of sequences (spans) a subject successfully remembered in the original order. This is a specific measure from the Spatial Span (SSP) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SSP assesses visuospatial working memory capacity. Count variable, ranging from 2 to 9, with higher scores indicating better memory performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in Forward Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4 | 7.6 score on a scale | Standard Deviation 1.3 |
| Monitoring | Mean Difference in Forward Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4 | 7.4 score on a scale | Standard Deviation 1.3 |
| Non-Users | Mean Difference in Forward Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4 | 7.6 score on a scale | Standard Deviation 1.4 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.05Mixed Models Analysis
Primary
Mean Difference in Number of Problems Correctly Solved on the First Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of trials where the subject chose the correct answer on the first attempt. This is a specific measure from the One Touch Stockings of Cambridge (OTS) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The OTS module assesses executive function based upon the Tower of Hanoi test. Count variable, ranging from 0 to 15, with higher scores indicating better performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in Number of Problems Correctly Solved on the First Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4 | 12.2 score on a scale | Standard Deviation 1.8 |
| Monitoring | Mean Difference in Number of Problems Correctly Solved on the First Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4 | 11.5 score on a scale | Standard Deviation 2.3 |
| Non-Users | Mean Difference in Number of Problems Correctly Solved on the First Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4 | 11.5 score on a scale | Standard Deviation 2.7 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.15Mixed Models Analysis
Primary
Mean Difference in Reverse Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4
The longest length of sequences (spans) a subject successfully remembered in the reverse order. This is a specific measure from the Spatial Span (SSP) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SSP assesses visuospatial working memory capacity. Count variable, ranging from 2 to 9, with higher scores indicating better memory performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in Reverse Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4 | 6.9 score on a scale | Standard Deviation 1.4 |
| Monitoring | Mean Difference in Reverse Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4 | 7 score on a scale | Standard Deviation 1.5 |
| Non-Users | Mean Difference in Reverse Span Length From Spatial Span (SSP) Module Averaged Over Weeks 1, 2, 3, and 4 | 6.9 score on a scale | Standard Deviation 1.6 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.532Mixed Models Analysis
Primary
Mean Difference in Stop Signal Reaction Time From Stop Signal Task (SST) Module Averaged Over Weeks 1, 2, 3, and 4
The estimate of the duration at which a person can successfully inhibit a response 50% of the time, represents the time before which all actions become ballistic and a subject is unable to cancel a response selection. This is a specific measure from the Stop Signal Task (SST) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SST module assesses response inhibition (impulse control). Response time variable in milliseconds (ms), ranging from 0 to 500 ms, with higher values indicating that it takes longer for a person to inhibit a response.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in Stop Signal Reaction Time From Stop Signal Task (SST) Module Averaged Over Weeks 1, 2, 3, and 4 | 210 score on a scale | Standard Deviation 35 |
| Monitoring | Mean Difference in Stop Signal Reaction Time From Stop Signal Task (SST) Module Averaged Over Weeks 1, 2, 3, and 4 | 219 score on a scale | Standard Deviation 49 |
| Non-Users | Mean Difference in Stop Signal Reaction Time From Stop Signal Task (SST) Module Averaged Over Weeks 1, 2, 3, and 4 | 222 score on a scale | Standard Deviation 56 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.038Mixed Models Analysis
Primary
Mean Difference in the Incongruency Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
The incongruency cost for each participant was defined as a summary (median) of response times for incongruent trials minus a summary (median) of response times for congruent trials. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Difference score in milliseconds (ms), ranging from -1900 to 1900 ms, with higher values indicating slower responses on incongruent trials, suggesting that it takes longer to process conflicting information.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Incongruency Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 37 score on a scale | Standard Deviation 33 |
| Monitoring | Mean Difference in the Incongruency Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 40 score on a scale | Standard Deviation 32 |
| Non-Users | Mean Difference in the Incongruency Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 43 score on a scale | Standard Deviation 37 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.898Mixed Models Analysis
Primary
Mean Difference in the Latency to First Correct Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4
The latency to first correct choice for each participant was defined as a summary (median) of the response times for all trials in which the subject picked the correct choice on the first attempt. This is a specific measure from the One Touch Stockings of Cambridge (OTS) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The OTS module assesses executive function based upon the Tower of Hanoi test. Response time variable in milliseconds (ms), a positive unbounded variable, with higher values indicating slower performance across correct trials.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Latency to First Correct Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4 | 7036 score on a scale | Standard Deviation 2794 |
| Monitoring | Mean Difference in the Latency to First Correct Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4 | 6690 score on a scale | Standard Deviation 2283 |
| Non-Users | Mean Difference in the Latency to First Correct Choice From the One Touch Stockings of Cambridge (OTS) Module Averaged Over Weeks 1, 2, 3, and 4 | 6851 score on a scale | Standard Deviation 3183 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.525Mixed Models Analysis
Primary
Mean Difference in the Multitasking Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
The multitasking cost for each participant was defined as a summary (median) of response times for the multi-task blocks (trials alternated between having to respond to the direction or position of the arrow) minus a summary (median) of response times for the single-task blocks (all trials consisted of either responding to the direction or position of the arrow). This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Difference score in milliseconds (ms), ranging from -1900 to 1900 ms, with higher values indicating slower responses on multi-task blocks, suggesting that it takes longer to process multiple sources of information.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Multitasking Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 96 score on a scale | Standard Deviation 71 |
| Monitoring | Mean Difference in the Multitasking Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 71 score on a scale | Standard Deviation 68 |
| Non-Users | Mean Difference in the Multitasking Cost From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 81 score on a scale | Standard Deviation 81 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.068Mixed Models Analysis
Primary
Mean Difference in the Participant's Strategy for 6-8 Box Conditions From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4
The number of times subjects began a new search from the same box they started on in previous trials. It is assumed that a person who begins from the same box each time is using a planned strategy to find the tokens. This is a specific measure from the Spatial Working Memory (SWM) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SWM module provides a measure of strategy as well as working memory errors. Count variable, ranging from 2 to 14, with higher scores indicating low strategy, meaning a subject began searches from many different boxes.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Participant's Strategy for 6-8 Box Conditions From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4 | 5.4 score on a scale | Standard Deviation 2.6 |
| Monitoring | Mean Difference in the Participant's Strategy for 6-8 Box Conditions From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4 | 5.7 score on a scale | Standard Deviation 2.6 |
| Non-Users | Mean Difference in the Participant's Strategy for 6-8 Box Conditions From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4 | 6.1 score on a scale | Standard Deviation 2.7 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.296Mixed Models Analysis
Primary
Mean Difference in the Response Latency From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
The response latency for each participant was defined as a summary (median) computed over their response times for all correct responses irrespective of condition. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Response time variable in milliseconds (ms), ranging from 100 to 2000 ms, with higher values indicating slower performance across all trials.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Response Latency From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 474 score on a scale | Standard Deviation 72 |
| Monitoring | Mean Difference in the Response Latency From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 468 score on a scale | Standard Deviation 78 |
| Non-Users | Mean Difference in the Response Latency From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 482 score on a scale | Standard Deviation 86 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.836Mixed Models Analysis
Primary
Mean Difference in the Total Number Correct in the Delayed Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of distinct words a subject correctly recalled from the studied list of 18 words during the delayed free recall phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 18, with higher scores indicating better immediate recall performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Total Number Correct in the Delayed Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 6.5 score on a scale | Standard Deviation 2.8 |
| Monitoring | Mean Difference in the Total Number Correct in the Delayed Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 6.5 score on a scale | Standard Deviation 3 |
| Non-Users | Mean Difference in the Total Number Correct in the Delayed Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 7.2 score on a scale | Standard Deviation 3.1 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.369Mixed Models Analysis
Primary
Mean Difference in the Total Number Correct in the Delayed Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of words a subject correctly identified as either previously studied or novel during the delayed recognition phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 36, with higher scores indicating better recognition memory performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Total Number Correct in the Delayed Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 30.5 score on a scale | Standard Deviation 3 |
| Monitoring | Mean Difference in the Total Number Correct in the Delayed Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 30.9 score on a scale | Standard Deviation 3.6 |
| Non-Users | Mean Difference in the Total Number Correct in the Delayed Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 30.3 score on a scale | Standard Deviation 4 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.511Mixed Models Analysis
Primary
Mean Difference in the Total Number Correct in the Immediate Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of distinct words a subject correctly recalled from the studied list of 18 words during the immediate free recall phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 18, with higher scores indicating better immediate recall performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Total Number Correct in the Immediate Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 7.3 score on a scale | Standard Deviation 2.3 |
| Monitoring | Mean Difference in the Total Number Correct in the Immediate Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 7.3 score on a scale | Standard Deviation 2.5 |
| Non-Users | Mean Difference in the Total Number Correct in the Immediate Recall Measure From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 7.7 score on a scale | Standard Deviation 2.7 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.226Mixed Models Analysis
Primary
Mean Difference in the Total Number Correct in the Immediate Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of words a subject correctly identified as either previously studied or novel during the immediate recognition phase. This is a specific measure from the Verbal Recognition Memory (VRM) Module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The VRM module assesses verbal memory and new learning. Count variable, ranging from 0 to 36, with higher scores indicating better recognition memory performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Total Number Correct in the Immediate Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 32.3 score on a scale | Standard Deviation 2.1 |
| Monitoring | Mean Difference in the Total Number Correct in the Immediate Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 32.4 score on a scale | Standard Deviation 2.9 |
| Non-Users | Mean Difference in the Total Number Correct in the Immediate Recognition Condition From the Verbal Recognition Memory (VRM) Module Averaged Over Weeks 1, 2, 3, and 4 | 31.9 score on a scale | Standard Deviation 3.1 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.647Mixed Models Analysis
Primary
Mean Difference in the Total Number Incorrect From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4
The total number of words a subject correctly identified as either previously studied or novel during the delayed recognition phase. This is a specific measure from the Multitasking Test (MTT) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The MTT assesses the participant's ability to manage conflicting information provided by the direction of an arrow and its location on the screen and to ignore task-irrelevant information. Count variable, ranging from 0 to 160, with higher scores indicating more errors and worse performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Total Number Incorrect From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 7.1 score on a scale | Standard Deviation 5.6 |
| Monitoring | Mean Difference in the Total Number Incorrect From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 8.5 score on a scale | Standard Deviation 7.7 |
| Non-Users | Mean Difference in the Total Number Incorrect From the Multitasking Test (MTT) Module Averaged Over Weeks 1, 2, 3, and 4 | 9.1 score on a scale | Standard Deviation 8.1 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.312Mixed Models Analysis
Primary
Mean Difference in the Total Number of Between Errors From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4
The number of times a subject incorrectly revisited a box that had contained a token in a previous trial across the 4, 6, and 8 box conditions. This is a specific measure from the Spatial Working Memory (SWM) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The SWM module provides a measure of strategy as well as working memory errors. Count variable, ranging from 0 to 63, with higher scores indicating worse performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Total Number of Between Errors From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4 | 3.6 score on a scale | Standard Deviation 5.4 |
| Monitoring | Mean Difference in the Total Number of Between Errors From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4 | 4.6 score on a scale | Standard Deviation 6.3 |
| Non-Users | Mean Difference in the Total Number of Between Errors From the Spatial Working Memory (SWM) Module Averaged Over Weeks 1, 2, 3, and 4 | 5.5 score on a scale | Standard Deviation 7.7 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.576Mixed Models Analysis
Primary
Mean Difference in the Total Number of Errors From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4
The number of times the subject chose the incorrect box for a stimulus on assessment problems plus an adjustment for the estimated number of errors they would have made on any problems/attempts/recalls they did not reach. This is a specific measure from the Paired Associates Learning (PAL) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The PAL module assesses visual memory and new learning. Count variable, ranging from 0 to 70, where higher scores indicate more errors and worse performance.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Total Number of Errors From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4 | 5.6 score on a scale | Standard Deviation 6.4 |
| Monitoring | Mean Difference in the Total Number of Errors From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4 | 6.2 score on a scale | Standard Deviation 7.7 |
| Non-Users | Mean Difference in the Total Number of Errors From Paired Associates Learning (PAL) Module Averaged Over Weeks 1, 2, 3, and 4 | 5.9 score on a scale | Standard Deviation 8.1 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.215Mixed Models Analysis
Secondary
Mean Difference in the Measure of Discriminability - A' From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4
A transformation of the proportion of hits and false alarms, providing an estimate of a subject's ability to detect the target sequences of digits after controlling for response bias (i.e., biases to respond or not respond irrespective of the stimuli on screen). This is a specific measure from the Rapid Visual Information Processing (RVP) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The RVP module assesses sustained attention. Bounded continuous variable, ranging from 0 to 1, where higher scores indicate a greater ability to discriminate between targets and distractors.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Measure of Discriminability - A' From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4 | 0.94 score on a scale | Standard Deviation 0.05 |
| Monitoring | Mean Difference in the Measure of Discriminability - A' From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4 | 0.93 score on a scale | Standard Deviation 0.06 |
| Non-Users | Mean Difference in the Measure of Discriminability - A' From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4 | 0.92 score on a scale | Standard Deviation 0.08 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.65Mixed Models Analysis
Secondary
Mean Difference in the Reponse Latency for Hits From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4
The response latency for hits for each participant was defined as a summary (median) over the set of response times for all correct responses (identification of target 3-digit sequences). This is a specific measure from the Rapid Visual Information Processing (RVP) module, which is part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The RVP module assesses sustained attention. Response time variable in milliseconds (ms), ranging from 100 to 1900 ms, with higher values indicating slower performance in detecting targets.
Time frame: 1, 2, 3, and 4 Weeks
Population: Pre-specified confirmatory analyses assessed differences between the abstinent and monitoring arms only (see attached Statistical Analysis Plan).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Abstinent | Mean Difference in the Reponse Latency for Hits From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4 | 422 score on a scale | Standard Deviation 51 |
| Monitoring | Mean Difference in the Reponse Latency for Hits From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4 | 428 score on a scale | Standard Deviation 97 |
| Non-Users | Mean Difference in the Reponse Latency for Hits From the Rapid Visual Information Processing (RVP) Module Averaged Over Weeks 1, 2, 3, and 4 | 428 score on a scale | Standard Deviation 78 |
Comparison: The mean difference in scale scores between the abstinence and monitoring groups was estimated via a binomial model with a dummy-coded contrast (0 for monitoring, 1 for abstinence). The model adjusted for change at weeks 2, 3, and 4 of the study, and for a subject's scale scores at baseline.p-value: 0.223Mixed Models Analysis