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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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Reduced Use Condition | Experimental | 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. |
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| Control Condition | No Intervention | 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. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Mobile contingency management | Behavioral | 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. |
| Measure | Description | Time Frame |
|---|---|---|
| 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. | Baseline and post-treatment (approximately eight weeks) |
| 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. | Baseline and post-treatment (approximately eight weeks) |
| 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. | Baseline and post-treatment (approximately eight weeks) |
| 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: Baseline and post-treatment (approximately eight weeks) |
| Measure | Description | Time Frame |
|---|---|---|
| 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. | Baseline and post-treatment (approximately eight weeks) |
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Inclusion Criteria:
Exclusion Criteria:
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Duke University Medical Center | Durham | North Carolina | 27706 | United States |
There is no plan to share individual participant data.
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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.
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| ID | Title | Description |
|---|---|---|
| FG000 | 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. |
| FG001 | 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. |
| Title | Milestones | Reasons Not Completed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
|
One participant was excluded from the analyses because the participant's reported mean daily cannabis use in grams was higher than five standard deviations of the rest of the sample, suggesting inaccurate reporting.
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| ID | Title | Description |
|---|---|---|
| BG000 | 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. |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous | Mean |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | score on a scale | Baseline and post-treatment (approximately eight weeks) |
|
9 weeks
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | 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. |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Angela Kirby | Duke University School of Medicine | 9198247729 | angela.kirby@duke.edu |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | Aug 16, 2022 | Dec 4, 2023 | Prot_SAP_000.pdf |
| ICF | No | No | Yes | Informed Consent Form | Jul 11, 2023 | Dec 4, 2023 | ICF_001.pdf |
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| ID | Term |
|---|---|
| D002189 | Marijuana Abuse |
| ID | Term |
|---|---|
| D019966 | Substance-Related Disorders |
| D064419 | Chemically-Induced Disorders |
| D001523 | Mental Disorders |
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|
| 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. |
| Baseline and post-treatment (approximately eight weeks) |
| 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. | Baseline and post-treatment (approximately eight weeks) |
| 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). | Baseline and post-treatment (approximately eight weeks) |
| 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. | Baseline and post-treatment (approximately eight weeks) |
| 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. | Baseline and post-treatment (approximately eight weeks) |
| 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. | Baseline and post-treatment (approximately eight weeks) |
| BG001 | 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. |
| BG002 | Total | Total of all reporting groups |
| years |
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| Sex: Female, Male | Count of Participants | Participants |
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| Ethnicity (NIH/OMB) | Count of Participants | Participants |
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| Race (NIH/OMB) | Count of Participants | Participants |
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| Region of Enrollment | Count of Participants | Participants |
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| OG001 | 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. |
|
|
| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | score on a scale | Baseline and post-treatment (approximately eight weeks) |
|
|
|
| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | score on a scale | Baseline and post-treatment (approximately eight weeks) |
|
|
|
| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | units on a scale | Time Frame: Baseline and post-treatment (approximately eight weeks) |
|
|
|
| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | score on a scale | Baseline and post-treatment (approximately eight weeks) |
|
|
|
| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | score on a scale | Baseline and post-treatment (approximately eight weeks) |
|
|
|
| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | score on a scale | Baseline and post-treatment (approximately eight weeks) |
|
|
|
| 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). | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | score on a scale | Baseline and post-treatment (approximately eight weeks) |
|
|
|
| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | score on a scale | Baseline and post-treatment (approximately eight weeks) |
|
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|
| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | units on a scale | Baseline and post-treatment (approximately eight weeks) |
|
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| 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. | Some participants were withdrawn from analyses due to missing data at the post-treatment visit. | Posted | Mean | Standard Deviation | days per month | Baseline and post-treatment (approximately eight weeks) |
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| 0 |
| 40 |
| 0 |
| 40 |
| 0 |
| 40 |
| EG001 | 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. | 0 | 19 | 0 | 19 | 0 | 19 |
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