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

Cannabis Clinical Trial

Official title:

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

Clinical Trial Details — Status: Enrolling by invitation

Administrative data

• NCT number: NCT05160688
• Other study ID #: 21-4899
• Status: Enrolling by invitation
• Phase: N/A
• Start date: May 5, 2023
• Est. completion date: February 1, 2026

Study information

• Verified date: July 2023
• Source: University of Colorado, Denver
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Enrolling by invitation
• Enrollment: 100
• Est. completion date: February 1, 2026
• Est. primary completion date: February 1, 2026
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 31 Years to 47 Years

Eligibility

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.

Related Conditions & MeSH terms

• Cannabis
• Marijuana Abuse
• Mental Disorders
• Problem Behavior

Intervention

Behavioral:
• Contingency management
Participants will be paid to abstain from cannabis use.

Locations

Country	Name	City	State
United States	Jessica M Ross	Aurora	Colorado

Sponsors (2)

Lead Sponsor	Collaborator
University of Colorado, Denver	University of Colorado, Boulder

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Change in attention performance	Flanker Inhibitory Control and Attention Test on NIH Toolbox: Composite score of accuracy and reaction time	Change from baseline to day 42
Primary	Change in episodic memory	Picture Sequence Memory Test on NIH Toolbox: Cumulative number of correct adjacent pairs	Change from baseline to day 42
Primary	Change in working memory	List Sorting Working Memory Test on NIH Toolbox: Total items correct across all trials	Change from baseline to day 42
Primary	Change in receptive vocabulary	Picture Vocabulary Test on NIH Toolbox: Computer adaptive testing	Change from baseline to day 42
Primary	Change in reading decoding	Oral Reading Recognition Test: Number of letters and words read correctly	Change from baseline to day 42
Primary	Change in immediate memory/verbal learning	Auditory Verbal Learning Test on NIH Toolbox: Total number of words recalled	Change from baseline to day 4
Primary	Change in pattern comparison processing speed	Pattern Comparison Processing Speed Test: Total number of correct responses	Change from baseline to day 42
Primary	Change in oral symbol digit test processing speed	Oral Symbol Digit Test on NIH Toolbox: Total number of correctly identified symbols	Change from baseline to day 42
Primary	Change in attention and executive function	Dimensional Change Card Sort Test on NIH Toolbox: Composite score of accuracy and correct answers	Change from baseline to day 42
Secondary	Change in anxiety symptoms	Beck Anxiety Inventory: Total score. Scores range from 0-63 and higher scores indicate higher levels of anxiety.	Change from baseline to day 42
Secondary	Change in depressive symptoms	Beck Depression Inventory: Total score. Scores range from 0-63 and higher scores indicate greater levels of depression.	Change from baseline to day 42
Secondary	Change in attention deficit/hyperactivity disorder symptoms	Adult Self-Report Scale: Total score. Scores range from 0-72 and higher scores indicate greater level of symptoms of attention deficit/hyperactivity disorder.	Change from baseline to day 42