Cannabis Use Disorder
Conditions
Keywords
marijuana, attentional bias, stress, buspirone
Brief summary
This project has two primary goals. The first goal is to further scientific understanding about marijuana abuse by examining two recognized factors in marijuana use and relapse: (1) stress/anxiety and (2) atypical reactivity to marijuana-related stimuli (e.g., attentional bias). The second goal is to attenuate the influence of stress/anxiety and attentional bias to marijuana stimuli via administration of buspirone. Buspirone is uniquely suited to this project because it has effects on neurotransmitter systems known to modulate both stress/anxiety and attentional bias.
Detailed description
For nearly 40 years marijuana has remained the most widely used illicit drug in the US, with more than 50% of first-time users \< age 18. Marijuana accounts for ≈ 60% of illicit substance use disorders (SUD) in the US, bearing by percent the largest US public health burden among illicit substances. Across preclinical, human laboratory, and clinical interview data, there is compelling evidence that the phenomenon of cue reactivity is related to drug seeking and relapse. Attentional bias is a measurable component of cue reactivity, and can be operationally defined as differential attention (e.g., reaction time difference) towards drug-related stimuli vs. neutral stimuli. This phenomenon has been demonstrated in SUD populations across many classes of abused drugs, including alcohol, nicotine, stimulants, opiates, and - importantly - marijuana. Cue reactivity and attentional bias are exacerbated by acute and chronic stress and anxiety. Notably, stress is a well-documented predictor of marijuana abuse and marijuana relapse. Therapeutic interventions that attenuate attentional bias to marijuana cues are a potentially important component in the treatment of marijuana SUD. Due to the well-documented association with stress, an intervention that simultaneously addresses both stress and attentional bias could be uniquely efficacious. Currently, few pharmacotherapies exist for marijuana SUD, and none are presently known to address attentional bias to marijuana cues. This application will explore the potential of the anxiolytic buspirone to modify attentional bias and stress. Buspirone is a unique compound marked by modulation of both serotonin (5-HT1A) and dopamine D3 receptors. Importantly, the 5-HT1A receptor is known to play a key role in stress related anxiety, and preclinical work indicates that D3 antagonists significantly decrease cue reactivity to a number of abused drugs. This combination of effects suggests buspirone may be advantageous in targeting both stress and attentional bias as factors that contribute to problem marijuana use. Accordingly, this project seeks to examine the effects of chronic buspirone administration on attentional bias and stress/anxiety in marijuana SUD. Using laboratory-based methodologies sensitive to attentional bias towards marijuana cues and well validated measures of stress and anxiety, we will examine if buspirone's unique mechanism of action will (a) produce an attenuation of attentional bias to marijuana cues, and (b) be most pronounced under conditions in which attentional bias is related to high levels of stress and anxiety.
Interventions
DRUGBuspirone
Buspirone is an anxiolytic compound marked by modulation of both 5-HT1A and D3 receptors. Buspirone is administered orally twice per day (9:00 AM and 6:00 PM) for 3 weeks. 10 mg buspirone is administered on days 1-4, then the dose is increased by 10 mg every 3 days to a maximum of 40 mg buspirone on days 10-19.
DRUGPlacebo
Placebo is administered orally twice per day (9:00 AM and 6:00 PM) for 3 weeks.
Sponsors
National Institute on Drug Abuse (NIDA)
The University of Texas Health Science Center, Houston
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
No
Inclusion criteria
* Marijuana substance use disorder based on a score of ≥ 13 on the Cannabis Use Disorders Identification Test - Revised (CUDIT-R) * a score of ≥ 4 on the Cannabis Abuse Screening Test (CAST) * meeting criteria for a marijuana substance use disorder based on the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV)
Exclusion criteria
* Current DSM-IV Axis I disorder other than marijuana use disorder * serious medical illness requiring ongoing medical treatment, which could affect the central nervous system, or any other medical contraindication (e.g., renal, cardiovascular, pulmonary, blood) as determined by medical screening * a positive pregnancy test or breast feeding (females) * concomitant use of prescription medications that could affect the central nervous system * active suicidal ideation or Beck Depression Inventory II score greater than 19 * positive urine drug screen for drugs other than marijuana or positive breath alcohol screen * Shipley-2 test of cognitive aptitude score outside 2 SD units of the published composite score average * smoking \> 10 nicotine cigarettes per day / Fagerstrom Score \> 4 * taking meds known to have significant drug interactions with buspirone.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements | week 1 | Eye movements are analyzed using a MiraMetrix S2 Eyetracker. This outcome measure reports a ratio: \[(number of anti-saccade errors with marijuana-related images) divided by (total number of anti-saccade errors with marijuana-related images or neutral images)\]. Anti-saccade errors are when the subject fails to inhibit fixation onto the image. |
| Stress as Assessed by the Perceived Stress Scale | week 1 | The Perceived Stress Scale is a 10 item scale that was developed to measure the degree to which individuals appraise their life as stressful and has been widely used in health studies. The scale has a 5-point Likert response format. The total score is calculated by summing responses. The questions are general in nature and relatively content free with regard to specific population groups. The range of scores is 0-40, with 40 indicating the most stress. |
| Anxiety as Assessed by the Zung Self-Rated Anxiety Scale | week 1 | The Zung Self-Rated Anxiety Scale is a widely-used 20 item scale that is scored on a Likert-type scale of 1-4, with 15 questions concerning increasing anxiety levels and five questions concerning decreasing anxiety levels. The scale focuses on the most common general anxiety symptoms and means of coping with stressors that produce anxiety. The range of scores is 20-80: * 20-44 Normal Range * 45-59 Mild to Moderate Anxiety Levels * 60-74 Marked to Severe Anxiety Levels * 75-80 Extreme Anxiety Levels |
| Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C) | week 1 | With the Visual Analogue Stress Scale - Current (VASS-C), current stress level is ranked on a 0 - 10 visual analog scale, with 0 as no stress and 10 as extreme stress, cued by the question Please rate your current stress level. |
Countries
United States
Participant flow
Pre-assignment details
45 were enrolled (i.e., screened and consented), but 3 participants never returned to begin the study. Thus, only 42 participants began the study.
Participants by arm
| Arm | Count |
|---|---|
| Buspirone Buspirone is administered orally twice per day (9:00 AM and 6:00 PM) for 3 weeks. 10 mg buspirone is administered on days 1-4, then the dose is increased by 10 mg every 3 days to a maximum of 40 mg buspirone on days 10-19. | 19 |
| Placebo Placebo is administered orally twice per day (9:00 AM and 6:00 PM) for 3 weeks. | 23 |
| Total | 42 |
Baseline characteristics
| Characteristic | Buspirone | Placebo | Total |
|---|---|---|---|
| Age, Continuous | 29.16 years STANDARD_DEVIATION 7.15 | 29.52 years STANDARD_DEVIATION 6.89 | 29.34 years STANDARD_DEVIATION 7.02 |
| Region of Enrollment United States | 19 participants | 23 participants | 42 participants |
| Sex: Female, Male Female | 8 Participants | 10 Participants | 18 Participants |
| Sex: Female, Male Male | 11 Participants | 13 Participants | 24 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 1 / 19 | 0 / 23 |
| serious Total, serious adverse events | 0 / 19 | 0 / 23 |
Outcome results
Primary
Anxiety as Assessed by the Zung Self-Rated Anxiety Scale
The Zung Self-Rated Anxiety Scale is a widely-used 20 item scale that is scored on a Likert-type scale of 1-4, with 15 questions concerning increasing anxiety levels and five questions concerning decreasing anxiety levels. The scale focuses on the most common general anxiety symptoms and means of coping with stressors that produce anxiety. The range of scores is 20-80: * 20-44 Normal Range * 45-59 Mild to Moderate Anxiety Levels * 60-74 Marked to Severe Anxiety Levels * 75-80 Extreme Anxiety Levels
Time frame: week 3
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Anxiety as Assessed by the Zung Self-Rated Anxiety Scale | 33.27778 units on a scale | Standard Deviation 4.884616 |
| Placebo | Anxiety as Assessed by the Zung Self-Rated Anxiety Scale | 31.63158 units on a scale | Standard Deviation 4.125941 |
Primary
Anxiety as Assessed by the Zung Self-Rated Anxiety Scale
The Zung Self-Rated Anxiety Scale is a widely-used 20 item scale that is scored on a Likert-type scale of 1-4, with 15 questions concerning increasing anxiety levels and five questions concerning decreasing anxiety levels. The scale focuses on the most common general anxiety symptoms and means of coping with stressors that produce anxiety. The range of scores is 20-80: * 20-44 Normal Range * 45-59 Mild to Moderate Anxiety Levels * 60-74 Marked to Severe Anxiety Levels * 75-80 Extreme Anxiety Levels
Time frame: week 2
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Anxiety as Assessed by the Zung Self-Rated Anxiety Scale | 31.5 units on a scale | Standard Deviation 3.714043 |
| Placebo | Anxiety as Assessed by the Zung Self-Rated Anxiety Scale | 31.57895 units on a scale | Standard Deviation 3.79057 |
Primary
Anxiety as Assessed by the Zung Self-Rated Anxiety Scale
The Zung Self-Rated Anxiety Scale is a widely-used 20 item scale that is scored on a Likert-type scale of 1-4, with 15 questions concerning increasing anxiety levels and five questions concerning decreasing anxiety levels. The scale focuses on the most common general anxiety symptoms and means of coping with stressors that produce anxiety. The range of scores is 20-80: * 20-44 Normal Range * 45-59 Mild to Moderate Anxiety Levels * 60-74 Marked to Severe Anxiety Levels * 75-80 Extreme Anxiety Levels
Time frame: week 1
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Anxiety as Assessed by the Zung Self-Rated Anxiety Scale | 32.44444 units on a scale | Standard Deviation 2.955 |
| Placebo | Anxiety as Assessed by the Zung Self-Rated Anxiety Scale | 32.52632 units on a scale | Standard Deviation 4.880442 |
Primary
Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements
Eye movements are analyzed using a MiraMetrix S2 Eyetracker. This outcome measure reports a ratio: \[(number of anti-saccade errors with marijuana-related images) divided by (total number of anti-saccade errors with marijuana-related images or neutral images)\]. Anti-saccade errors are when the subject fails to inhibit fixation onto the image.
Time frame: week 1
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements | 0.5795019 ratio of errors (see OM description) | Standard Deviation 0.1609511 |
| Placebo | Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements | 0.5539831 ratio of errors (see OM description) | Standard Deviation 0.1442601 |
Primary
Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements
Eye movements are analyzed using a MiraMetrix S2 Eyetracker. This outcome measure reports a ratio: \[(number of anti-saccade errors with marijuana-related images) divided by (total number of anti-saccade errors with marijuana-related images or neutral images)\]. Anti-saccade errors are when the subject fails to inhibit fixation onto the image.
Time frame: week 2
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements | 0.5517691 ratio of errors (see OM description) | Standard Deviation 0.1319968 |
| Placebo | Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements | 0.4979594 ratio of errors (see OM description) | Standard Deviation 0.1486691 |
Primary
Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements
Eye movements are analyzed using a MiraMetrix S2 Eyetracker. This outcome measure reports a ratio: \[(number of anti-saccade errors with marijuana-related images) divided by (total number of anti-saccade errors with marijuana-related images or neutral images)\]. Anti-saccade errors are when the subject fails to inhibit fixation onto the image.
Time frame: week 3
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements | 0.5503957 ratio of errors (see OM description) | Standard Deviation 0.1133407 |
| Placebo | Attentional Bias to Marijuana Specific Stimuli Measured Via Analysis of Eye Movements | 0.531073 ratio of errors (see OM description) | Standard Deviation 0.1991689 |
Primary
Stress as Assessed by the Perceived Stress Scale
The Perceived Stress Scale is a 10 item scale that was developed to measure the degree to which individuals appraise their life as stressful and has been widely used in health studies. The scale has a 5-point Likert response format. The total score is calculated by summing responses. The questions are general in nature and relatively content free with regard to specific population groups. The range of scores is 0-40, with 40 indicating the most stress.
Time frame: week 3
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Stress as Assessed by the Perceived Stress Scale | 10.38889 units on a scale | Standard Deviation 6.436467 |
| Placebo | Stress as Assessed by the Perceived Stress Scale | 14.05263 units on a scale | Standard Deviation 7.799385 |
Primary
Stress as Assessed by the Perceived Stress Scale
The Perceived Stress Scale is a 10 item scale that was developed to measure the degree to which individuals appraise their life as stressful and has been widely used in health studies. The scale has a 5-point Likert response format. The total score is calculated by summing responses. The questions are general in nature and relatively content free with regard to specific population groups. The range of scores is 0-40, with 40 indicating the most stress.
Time frame: week 2
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Stress as Assessed by the Perceived Stress Scale | 13.88889 units on a scale | Standard Deviation 6.434182 |
| Placebo | Stress as Assessed by the Perceived Stress Scale | 16.42105 units on a scale | Standard Deviation 5.708822 |
Primary
Stress as Assessed by the Perceived Stress Scale
The Perceived Stress Scale is a 10 item scale that was developed to measure the degree to which individuals appraise their life as stressful and has been widely used in health studies. The scale has a 5-point Likert response format. The total score is calculated by summing responses. The questions are general in nature and relatively content free with regard to specific population groups. The range of scores is 0-40, with 40 indicating the most stress.
Time frame: week 1
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Stress as Assessed by the Perceived Stress Scale | 15.05556 units on a scale | Standard Deviation 5.885898 |
| Placebo | Stress as Assessed by the Perceived Stress Scale | 18.57895 units on a scale | Standard Deviation 6.551639 |
Primary
Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C)
With the Visual Analogue Stress Scale - Current (VASS-C), current stress level is ranked on a 0 - 10 visual analog scale, with 0 as no stress and 10 as extreme stress, cued by the question Please rate your current stress level.
Time frame: week 1
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C) | 3.888889 units on a scale | Standard Deviation 2.373602 |
| Placebo | Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C) | 3.631579 units on a scale | Standard Deviation 3.515213 |
Primary
Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C)
With the Visual Analogue Stress Scale - Current (VASS-C), current stress level is ranked on a 0 - 10 visual analog scale, with 0 as no stress and 10 as extreme stress, cued by the question Please rate your current stress level.
Time frame: week 2
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C) | 3 units on a scale | Standard Deviation 2.44949 |
| Placebo | Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C) | 2.789474 units on a scale | Standard Deviation 2.636895 |
Primary
Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C)
With the Visual Analogue Stress Scale - Current (VASS-C), current stress level is ranked on a 0 - 10 visual analog scale, with 0 as no stress and 10 as extreme stress, cued by the question Please rate your current stress level.
Time frame: week 3
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Buspirone | Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C) | 1.944444 units on a scale | Standard Deviation 1.862074 |
| Placebo | Stress as Assessed by the Visual Analogue Stress Scale-Current (VASS-C) | 2.526316 units on a scale | Standard Deviation 2.50263 |