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

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.

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.