Cannabis, Cannabis Use
Conditions
Brief summary
Nearly 20 million Americans report use of cannabis in the past month, and heavy cannabis use has increased by nearly 60% in the U.S. since 2007. Heavy cannabis use is associated with lower educational attainment, reduced physical activity, increased rates of addiction and unemployment, and neuropsychological deficits. Studies suggest that cannabis use is also associated with increased mental health symptoms, drugged driving, and traffic accidents. While there is evidence that sustained abstinence can lead to improvements in the functional outcomes of former users, the degree to which reductions alone (i.e., not sustained abstinence) in cannabis use might be associated with positive changes in functional outcomes is unknown. This is a critical gap in the literature, as many interventions for cannabis and other drugs are associated with decreases in frequency and quantity of use, but fail to achieve an effect on overall abstinence rates. The objective of the present research is to use ecological momentary assessment (EMA), a real-time, naturalistic data collection method, to prospectively study the impact of reduced cannabis use on functional outcomes in heavy cannabis users. Contingency management (CM) will be used to promote reductions in frequency and quantity of cannabis use. CM is an intensive behavioral therapy that is highly effective at producing short-term reductions in illicit drug use. We have recently developed a novel approach that leverages mobile technology and recent developments in cannabis testing. We have pilot-tested this approach with heavy cannabis users and found that it is an acceptable and feasible method. The present research will use this technology in conjunction with EMA methods to study the impact of reduced cannabis use on key functional outcomes. Our central hypothesis is that reductions in frequency and quantity of cannabis use will lead to positive changes in cannabis users' mental health, self-efficacy, physical activity, working memory, health-related quality of life, and driving behavior. The rationale for this research is that it will provide the first and only real-time data concerning the potential impact of reductions in cannabis use on functional outcomes. As such, the findings from the present research will directly inform ongoing efforts to include reductions in illicit drug use as a valid, clinically-meaningful outcome measure in clinical trials of pharmacotherapies for the treatment of substance use disorders.
Interventions
BEHAVIORALMobile contingency management
Mobile contingency management is a mobile-phone based behavioral therapy that provides positive reinforcement (i.e., money) for abstinence that is highly effective at reducing substance use.
Sponsors
Duke University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Report 40 or more days of cannabis use (other than ingested cannabis, i.e., edibles) in past 90 days * Can speak and write fluent conversational English * Are between 18 and 80 years of age * Are willing to attempt to reduce frequency of cannabis use * Complete at least 10 of the 14 nightly diaries during the ad lib phase of the study procedures.
Exclusion criteria
* Are expected to have an unstable medication regimen during the study * Are currently receiving non-study treatment for cannabis use disorder * Are pregnant or become pregnant * Meet criteria for a serious mental illness (e.g., bipolar disorder, schizophrenia) * Meet criteria for a substance use disorder other than nicotine or cannabis use disorders * Are currently imprisoned or in psychiatric hospitalization or become imprisoned or in psychiatric hospitalization * Report imminent risk for suicide or homicide * Meet criteria for bio-verified sustained abstinence (i.e., all of their saliva tests are negative during the 6-week experimental phase of the study)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Mental Health Symptoms | Baseline and post-treatment (approximately eight weeks) | Mental health symptoms will be measured by the 90-item Symptom Checklist (SCL-90). This measure has a scoring range of 0 to 360, with lower scores indicating lower distress related to mental health. |
| Change in Self-reported Self-efficacy | Baseline and post-treatment (approximately eight weeks) | Self-efficacy will be measured by the Marijuana Reduction Strategies Self-Efficacy Scale. This measure has a scoring range of 0 to 84, with higher scores indicating increased self-efficacy. |
| Change in Physical Activity as Measured by the Leisure-Time Physical Activity Questionnaire | Baseline and post-treatment (approximately eight weeks) | Physical activity will be measured using the Leisure-Time Physical Activity Questionnaire. Scores range from 0 to 99, with higher scores indicating increased physical activity. |
| Change in Physical Activity as Measured by the International Physical Activity Questionnaire | Time Frame: Baseline and post-treatment (approximately eight weeks) | Physical activity will be measured using a continuous score on the International Physical Activity Questionnaire. The score is calculated by multiplying metabolic equivalents times minutes per day times days per week; scores range from 0 to 13,440. Higher scores indicate increased physical activity. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Impulsivity as Measured by the Balloon Analogue Risk Task | Baseline and post-treatment (approximately eight weeks) | Impulsivity will be measured with the Balloon Analogue Risk Task. Scores range from 0 to 128, and higher scores indicate higher impulsivity. |
| Change in Health-related Quality of Life, WHOQOL-BREF | Baseline and post-treatment (approximately eight weeks) | Health-related quality of life will be measured with the World Health Organization Quality of Life Brief (WHOQOL-BREF). The measure has a scoring range of 0 to 100, with higher scores indicating a higher quality of life. |
| Change in Number of Days of Drugged Driving | Baseline and post-treatment (approximately eight weeks) | Number of days of drugged driving in the past month will be self-reported by participants using a Timeline Follow-Back Interview. |
| Change in Impulsivity as Measured by Self-report | Baseline and post-treatment (approximately eight weeks) | Self-reported impulsivity will be measured with the Urgency, Premeditation (lack of), Perserverance (lack of), Sensation Seeking, Positive Urgency, Impulsive Behavior Scale (UPPS-P). The measure has a score range of 59 to 236. Higher scores indicate higher impulsivity. |
| Change in Visual Working Memory | Baseline and post-treatment (approximately eight weeks) | Visual working memory will be measured by the Visual Working Memory (VWM) Index of Wechsler Memory Scale, which is comprised of the Symbol Span and Spatial Addition subtests, whose scores are added together to create a VWM score. Although this scale has no minimum or maximum score, higher scores indicate better visual working memory. |
| Change in Auditory Working Memory | Baseline and post-treatment (approximately eight weeks) | Auditory working memory will be measured by the Auditory Working Memory (AWM) Index of Wechsler Memory Scale, which is comprised of the Digit Span and Letter-Number Sequencing subtests, whose scores are added together to create a AWM score. Although this scale has no minimum or maximum score, higher scores indicate better auditory working memory. |
| Change in Impulsivity as Measured by Delay Discounting (i.e., Iowa Gambling Task) | Baseline and post-treatment (approximately eight weeks) | Impulsivity will be measured with a delay discounting task called the Iowa Gambling Task. Scores range from -100 to 100. Higher scores indicate more advantageous choices (i.e., lower impulsivity). |
Countries
United States
Participant flow
Pre-assignment details
76 participants were deemed eligible for the study at screen. Six participants were withdrawn, dropped out, or lost to contact during the ad lib phase of the study, so were not randomized to a study group. Ten participants didn't meet the 10 of 14 nightly diary minimum during the ad lib phase of the study, so were withdrawn prior to randomization.
Participants by arm
| Arm | Count |
|---|---|
| Reduced Use Condition Participants in the reduced use condition will be provided mobile contingency management, in which they are paid to provide marijuana saliva readings that suggest they have been abstinent from marijuana use.
Mobile contingency management: Mobile contingency management is a mobile-phone based behavioral therapy that provides positive reinforcement (i.e., money) for abstinence that is highly effective at reducing substance use. | 40 |
| Control Condition Participants in the control condition will be asked to provide marijuana saliva readings, but they are not paid for abstinent readings. Instead, their payments are yoked to the average amount of payment made by two participants in the reduced use condition. | 19 |
| Total | 59 |
Baseline characteristics
| Characteristic | Reduced Use Condition | Total | Control Condition |
|---|---|---|---|
| Age, Continuous | 39 years STANDARD_DEVIATION 13.16 | 38.1 years STANDARD_DEVIATION 12.9 | 35.89 years STANDARD_DEVIATION 14.34 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants | 1 Participants | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 40 Participants | 58 Participants | 18 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 12 Participants | 20 Participants | 8 Participants |
| Race (NIH/OMB) More than one race | 4 Participants | 6 Participants | 2 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 24 Participants | 32 Participants | 8 Participants |
| Region of Enrollment United States | 40 Participants | 59 Participants | 19 Participants |
| Sex: Female, Male Female | 25 Participants | 40 Participants | 15 Participants |
| Sex: Female, Male Male | 15 Participants | 19 Participants | 4 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 40 | 0 / 19 |
| other Total, other adverse events | 0 / 40 | 0 / 19 |
| serious Total, serious adverse events | 0 / 40 | 0 / 19 |
Outcome results
Primary
Change in Mental Health Symptoms
Mental health symptoms will be measured by the 90-item Symptom Checklist (SCL-90). This measure has a scoring range of 0 to 360, with lower scores indicating lower distress related to mental health.
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Mental Health Symptoms | -0.02 score on a scale | Standard Deviation 0.31 |
| Control Condition | Change in Mental Health Symptoms | 0.11 score on a scale | Standard Deviation 0.41 |
Primary
Change in Physical Activity as Measured by the International Physical Activity Questionnaire
Physical activity will be measured using a continuous score on the International Physical Activity Questionnaire. The score is calculated by multiplying metabolic equivalents times minutes per day times days per week; scores range from 0 to 13,440. Higher scores indicate increased physical activity.
Time frame: Time Frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Physical Activity as Measured by the International Physical Activity Questionnaire | -855.22 units on a scale | Standard Deviation 5946.72 |
| Control Condition | Change in Physical Activity as Measured by the International Physical Activity Questionnaire | -439.23 units on a scale | Standard Deviation 5330.92 |
Primary
Change in Physical Activity as Measured by the Leisure-Time Physical Activity Questionnaire
Physical activity will be measured using the Leisure-Time Physical Activity Questionnaire. Scores range from 0 to 99, with higher scores indicating increased physical activity.
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Physical Activity as Measured by the Leisure-Time Physical Activity Questionnaire | -0.46 score on a scale | Standard Deviation 23.06 |
| Control Condition | Change in Physical Activity as Measured by the Leisure-Time Physical Activity Questionnaire | 4.07 score on a scale | Standard Deviation 16.05 |
Primary
Change in Self-reported Self-efficacy
Self-efficacy will be measured by the Marijuana Reduction Strategies Self-Efficacy Scale. This measure has a scoring range of 0 to 84, with higher scores indicating increased self-efficacy.
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Self-reported Self-efficacy | -4.13 score on a scale | Standard Deviation 56.4 |
| Control Condition | Change in Self-reported Self-efficacy | -16.07 score on a scale | Standard Deviation 30.47 |
Secondary
Change in Auditory Working Memory
Auditory working memory will be measured by the Auditory Working Memory (AWM) Index of Wechsler Memory Scale, which is comprised of the Digit Span and Letter-Number Sequencing subtests, whose scores are added together to create a AWM score. Although this scale has no minimum or maximum score, higher scores indicate better auditory working memory.
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Auditory Working Memory | 0.74 score on a scale | Standard Deviation 3.17 |
| Control Condition | Change in Auditory Working Memory | -0.43 score on a scale | Standard Deviation 2.59 |
Secondary
Change in Health-related Quality of Life, WHOQOL-BREF
Health-related quality of life will be measured with the World Health Organization Quality of Life Brief (WHOQOL-BREF). The measure has a scoring range of 0 to 100, with higher scores indicating a higher quality of life.
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Health-related Quality of Life, WHOQOL-BREF | 4.76 score on a scale | Standard Deviation 14.77 |
| Control Condition | Change in Health-related Quality of Life, WHOQOL-BREF | -1.93 score on a scale | Standard Deviation 12.31 |
Secondary
Change in Impulsivity as Measured by Delay Discounting (i.e., Iowa Gambling Task)
Impulsivity will be measured with a delay discounting task called the Iowa Gambling Task. Scores range from -100 to 100. Higher scores indicate more advantageous choices (i.e., lower impulsivity).
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Impulsivity as Measured by Delay Discounting (i.e., Iowa Gambling Task) | -5.89 score on a scale | Standard Deviation 51.92 |
| Control Condition | Change in Impulsivity as Measured by Delay Discounting (i.e., Iowa Gambling Task) | -0.14 score on a scale | Standard Deviation 30.92 |
Secondary
Change in Impulsivity as Measured by Self-report
Self-reported impulsivity will be measured with the Urgency, Premeditation (lack of), Perserverance (lack of), Sensation Seeking, Positive Urgency, Impulsive Behavior Scale (UPPS-P). The measure has a score range of 59 to 236. Higher scores indicate higher impulsivity.
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Impulsivity as Measured by Self-report | 1.16 units on a scale | Standard Deviation 14.16 |
| Control Condition | Change in Impulsivity as Measured by Self-report | 1.48 units on a scale | Standard Deviation 13.18 |
Secondary
Change in Impulsivity as Measured by the Balloon Analogue Risk Task
Impulsivity will be measured with the Balloon Analogue Risk Task. Scores range from 0 to 128, and higher scores indicate higher impulsivity.
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Impulsivity as Measured by the Balloon Analogue Risk Task | 5.58 score on a scale | Standard Deviation 10.96 |
| Control Condition | Change in Impulsivity as Measured by the Balloon Analogue Risk Task | 4.73 score on a scale | Standard Deviation 6.09 |
Secondary
Change in Number of Days of Drugged Driving
Number of days of drugged driving in the past month will be self-reported by participants using a Timeline Follow-Back Interview.
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Number of Days of Drugged Driving | -6.44 days per month | Standard Deviation 10.57 |
| Control Condition | Change in Number of Days of Drugged Driving | -2.58 days per month | Standard Deviation 7.73 |
Secondary
Change in Visual Working Memory
Visual working memory will be measured by the Visual Working Memory (VWM) Index of Wechsler Memory Scale, which is comprised of the Symbol Span and Spatial Addition subtests, whose scores are added together to create a VWM score. Although this scale has no minimum or maximum score, higher scores indicate better visual working memory.
Time frame: Baseline and post-treatment (approximately eight weeks)
Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Reduced Use Condition | Change in Visual Working Memory | 1.95 score on a scale | Standard Deviation 2.65 |
| Control Condition | Change in Visual Working Memory | -0.15 score on a scale | Standard Deviation 3.44 |