Clinical trial NCT05160688: Changes in Cognition and Psychiatric Disorder Symptoms During Cannabis Abstinence Using a Novel Discordant Twin Design
Official title: Changes in Cognition and Psychiatric Disorder Symptoms During Cannabis Abstinence Using a Novel Discordant Twin Design
Study type: INTERVENTIONAL
Overall status: ENROLLING_BY_INVITATION
Phase: NA
Conditions: Cannabis
Lead sponsor: University of Colorado, Denver
Sponsor class: OTHER
Collaborators: name: University of Colorado, Boulder
First posted: 2021-12-16
Enrollment: 100
Sex: ALL
Minimum age (years): 31
Maximum age (years): 47
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

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.

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.

Primary outcomes:
measure: Change in attention performance
timeFrame: Change from baseline to day 42
measure: Change in episodic memory
timeFrame: Change from baseline to day 42
measure: Change in working memory
timeFrame: Change from baseline to day 42
measure: Change in receptive vocabulary
timeFrame: Change from baseline to day 42
measure: Change in reading decoding
timeFrame: Change from baseline to day 42
measure: Change in immediate memory/verbal learning
timeFrame: Change from baseline to day 4
measure: Change in pattern comparison processing speed
timeFrame: Change from baseline to day 42
measure: Change in oral symbol digit test processing speed
timeFrame: Change from baseline to day 42
measure: Change in attention and executive function
timeFrame: Change from baseline to day 42
Secondary outcomes:
measure: Change in anxiety symptoms
timeFrame: Change from baseline to day 42
measure: Change in depressive symptoms
timeFrame: Change from baseline to day 42
measure: Change in attention deficit/hyperactivity disorder symptoms
timeFrame: Change from baseline to day 42
Other outcomes:
Locations:
city: Aurora
country: United States
facility: Jessica M Ross
state: Colorado
Study officials:
affiliation: University of Colorado, Denver
name: J. Megan Ross, Ph.D.
role: PRINCIPAL_INVESTIGATOR
References: