Trial Outcomes & Findings for Impact of Reduced Cannabis Use on Functional Outcomes (R33 Phase) (NCT NCT04567238)

NCT ID: NCT04567238

Last Updated: 2024-12-24

Results Overview

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.

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 60 participants
• Primary outcome timeframe: Baseline and post-treatment (approximately eight weeks)
• Results posted on: 2024-12-24

Participant Flow

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 Six participants were withdrawn, dropped out, or lost to contact during the ad lib phase of the study, so were not randomized to a study group. Ten participants didn't meet the 10 of 14 nightly diary minimum during the ad lib phase of the study, so were withdrawn prior to randomization.

Participant milestones

Measure	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.	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.
Overall Study STARTED	40	20
Overall Study COMPLETED	40	20
Overall Study NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Impact of Reduced Cannabis Use on Functional Outcomes (R33 Phase)

Baseline characteristics by cohort

Measure	Reduced Use Condition n=40 Participants 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.	Control Condition n=19 Participants 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.	Total n=59 Participants Total of all reporting groups
Age, Continuous	39 years STANDARD_DEVIATION 13.16 • n=5 Participants	35.89 years STANDARD_DEVIATION 14.34 • n=7 Participants	38.1 years STANDARD_DEVIATION 12.9 • n=5 Participants
Sex: Female, Male Female	25 Participants n=5 Participants	15 Participants n=7 Participants	40 Participants n=5 Participants
Sex: Female, Male Male	15 Participants n=5 Participants	4 Participants n=7 Participants	19 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants	1 Participants n=7 Participants	1 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	40 Participants n=5 Participants	18 Participants n=7 Participants	58 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	1 Participants n=7 Participants	1 Participants n=5 Participants
Race (NIH/OMB) Asian	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	12 Participants n=5 Participants	8 Participants n=7 Participants	20 Participants n=5 Participants
Race (NIH/OMB) White	24 Participants n=5 Participants	8 Participants n=7 Participants	32 Participants n=5 Participants
Race (NIH/OMB) More than one race	4 Participants n=5 Participants	2 Participants n=7 Participants	6 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Region of Enrollment United States	40 Participants n=5 Participants	19 Participants n=7 Participants	59 Participants n=5 Participants

PRIMARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

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.

Outcome measures

Measure	Reduced Use Condition n=38 Participants 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.	Control Condition n=15 Participants 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.
Change in Mental Health Symptoms	-0.02 score on a scale Standard Deviation 0.31	0.11 score on a scale Standard Deviation 0.41

PRIMARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

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.

Outcome measures

Measure	Reduced Use Condition n=34 Participants 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.	Control Condition n=15 Participants 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.
Change in Self-reported Self-efficacy	-4.13 score on a scale Standard Deviation 56.40	-16.07 score on a scale Standard Deviation 30.47

PRIMARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

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.

Outcome measures

Measure	Reduced Use Condition n=35 Participants 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.	Control Condition n=15 Participants 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.
Change in Physical Activity as Measured by the Leisure-Time Physical Activity Questionnaire	-0.46 score on a scale Standard Deviation 23.06	4.07 score on a scale Standard Deviation 16.05

PRIMARY outcome

Timeframe: 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.

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.

Outcome measures

Measure	Reduced Use Condition n=34 Participants 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.	Control Condition n=11 Participants 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.
Change in Physical Activity as Measured by the International Physical Activity Questionnaire	-855.22 units on a scale Standard Deviation 5946.72	-439.23 units on a scale Standard Deviation 5330.92

SECONDARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

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.

Outcome measures

Measure	Reduced Use Condition n=37 Participants 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.	Control Condition n=14 Participants 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.
Change in Health-related Quality of Life, WHOQOL-BREF	4.76 score on a scale Standard Deviation 14.77	-1.93 score on a scale Standard Deviation 12.31

SECONDARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

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.

Outcome measures

Measure	Reduced Use Condition n=37 Participants 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.	Control Condition n=13 Participants 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.
Change in Visual Working Memory	1.95 score on a scale Standard Deviation 2.65	-0.15 score on a scale Standard Deviation 3.44

SECONDARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

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.

Outcome measures

Measure	Reduced Use Condition n=38 Participants 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.	Control Condition n=14 Participants 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.
Change in Auditory Working Memory	0.74 score on a scale Standard Deviation 3.17	-0.43 score on a scale Standard Deviation 2.59

SECONDARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

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).

Outcome measures

Measure	Reduced Use Condition n=38 Participants 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.	Control Condition n=14 Participants 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.
Change in Impulsivity as Measured by Delay Discounting (i.e., Iowa Gambling Task)	-5.89 score on a scale Standard Deviation 51.92	-0.14 score on a scale Standard Deviation 30.92

SECONDARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

Impulsivity will be measured with the Balloon Analogue Risk Task. Scores range from 0 to 128, and higher scores indicate higher impulsivity.

Outcome measures

Measure	Reduced Use Condition n=33 Participants 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.	Control Condition n=12 Participants 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.
Change in Impulsivity as Measured by the Balloon Analogue Risk Task	5.58 score on a scale Standard Deviation 10.96	4.73 score on a scale Standard Deviation 6.09

SECONDARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

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.

Outcome measures

Measure	Reduced Use Condition n=35 Participants 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.	Control Condition n=15 Participants 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.
Change in Impulsivity as Measured by Self-report	1.16 units on a scale Standard Deviation 14.16	1.48 units on a scale Standard Deviation 13.18

SECONDARY outcome

Timeframe: Baseline and post-treatment (approximately eight weeks)

Population: Some participants were withdrawn from analyses due to missing data at the post-treatment visit.

Number of days of drugged driving in the past month will be self-reported by participants using a Timeline Follow-Back Interview.

Outcome measures

Measure	Reduced Use Condition n=36 Participants 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.	Control Condition n=19 Participants 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.
Change in Number of Days of Drugged Driving	-6.44 days per month Standard Deviation 10.57	-2.58 days per month Standard Deviation 7.73

Adverse Events

Reduced Use Condition

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Control Condition

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Angela Kirby

Duke University School of Medicine

Phone: 9198247729

Email: angela.kirby@duke.edu

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place