Changes in Cognition and Psychiatric Disorder Symptoms During Cannabis Abstinence Using a Novel Discordant Twin Design

NCT ID: NCT05160688

Last Updated: 2023-07-18

Basic Information

• Recruitment Status: ENROLLING_BY_INVITATION
• Clinical Phase: NA
• Total Enrollment: 100 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-05-05
• Study Completion Date: 2026-02-01

Brief Summary

This study will test whether 42 days of cannabis abstinence, compared to continued cannabis use, is associated with improvements in cognition and psychiatric disorder symptoms. Identical twins, who are concordant on cannabis use, will be experimentally-manipulated to be discordant for 42 days. Each twin, within a twin pair, will be randomly assigned to either the contingency management condition, incentive-based protocol to promote cannabis abstinence, or control condition, no changes in cannabis use requested.

Detailed Description

The proposed project is a randomized controlled trial to compare cognition and psychiatric disorder symptoms between monozygotic (MZ) twin pairs, who are concordant on frequency of cannabis use. Each twin, within the twin pair, will be randomly assigned to either contingency management (CM), monetary incentives provided to reinforce cannabis abstinence, or control, no changes in cannabis use required or reinforced. Participants in the CM condition will receive an increasing schedule of payments at each visit reinforcing continued cannabis abstinence. All participants will receive increases in the payment schedule for attendance of each subsequent assessment. Participants will be assessed on measures of cognition including attention, memory, and processing speed as well as anxiety, depression, and ADHD symptoms. In addition, at each visit participants will complete a qualitative and quantitative drug test. The qualitative drug test will be used to determine if new cannabis use has occurred since the last visit, and will determine if the participant receives payment for abstinence. The investigators will also use previously collected genotype for each participant.

The first aim of this study is to characterize cognitive recovery, across all potential cognitive domains, using an experimental manipulation to achieve discordance between MZ twins on cannabis use. The hypothesis for the first aim is that the abstinent group will have greater improvements in memory and processing speed compared to controls. However, there will not be any group differences between the abstinent group and the control group on attention, language, and executive function performance. The second aim of the proposed project is to characterize psychiatric disorder symptoms by comparing psychiatric disorder symptom changes among the cannabis abstaining twin to their cannabis using co-twin across 42 days. The abstinent group will endorse more psychiatric symptoms during the withdrawal period (up to 14 days) but will endorse fewer psychiatric symptoms at day 28 and 42 compared to the control group. The third aim (exploratory) of the proposed project is to examine how genetic risk for psychiatric disorders interacts with environment (i.e., cannabis abstinence versus continued use) to influence cognitive functioning. The hypothesis for aim 3 is that anxiety, depression, and ADHD polygenic scores will be more strongly associated with cognitive outcomes in the control group compared to the abstinent group.

Conditions

Cannabis

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Contingency management

Contingency management (CM) is an incentive-based intervention providing patients with tangible rewards as reinforcement for positive behaviors like abstinence from drug use. Incentives are provided with each urine sample that is drug-free and are increased with each subsequent drug-free urine sample. Participants in the CM condition will receive increasing payments for abstinence: $30 on day 3, $45 on day 5, $60 on day 7, $75 on day 14, $90 on day 21, $105 on day 28, and $120 on day 42. Participants in both conditions also receive increasing payment for visit attendance: $10 on day 1, $15 on day 3, $20 on day 5, $25 on day 7, $30 on day 14, $35 on day 21, $45 on day 28, and $55 on day 42. At the end of the baseline visit, participants in the CM condition will sign a behavioral contract with study staff that clearly outlines expectations as well as the payment schedule.

Group Type: EXPERIMENTAL

Contingency management

Intervention Type: BEHAVIORAL

Participants will be paid to abstain from cannabis use.

No intervention

Participants in this condition will be monitored and will not receive any compensation for cannabis abstinence.

Group Type: NO_INTERVENTION

No interventions assigned to this group

Interventions

Contingency management

Participants will be paid to abstain from cannabis use.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

1. Monozygotic (MZ) twin pair, in which both twins are willing to participate

2. MZ twin pair must be concordant in their frequency of cannabis use (+/- 2 days)

3. Cannabis use at least 1x per week on most weeks

4. Cannabis use in the past 7 days at the baseline visit

5. Positive qualitative urine toxicology at baseline for THC

6. Located within the state of Colorado

Exclusion Criteria

1) Discordance in the twin pairs on a significant, adverse experience, like traumatic brain injury.

• Minimum Eligible Age: 31 Years
• Maximum Eligible Age: 47 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Colorado, Boulder

OTHER

Sponsor Role: collaborator

University of Colorado, Denver

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

J. Megan Ross, Ph.D.

Role: PRINCIPAL_INVESTIGATOR

University of Colorado, Denver

Locations

Jessica M Ross

Aurora, Colorado, United States

Countries

United States

Other Identifiers

21-4899

Identifier Type: -

Identifier Source: org_study_id