Effects of Cannabis Abstinence on Symptomology and Cognition in Bipolar Disorder

Effects of Extended Cannabis Abstinence on Clinical and Cognitive Outcomes in Patients With Co-Morbid Bipolar Disorder and Cannabis Use Disorder

The objective of this study is to assess the changes in symptoms and cognition that occur after a 28-day abstinence period in patients with comorbid Cannabis Use Disorder (CUD) and Bipolar (Type I or II) disorder. Stabilized bipolar patients (N=52) with CUD will be randomly assigned to one of two groups: 1) A contingent reinforcement (CR) group (n=26); 2) a non-contingent reinforcement (NCR) group (n=26). The study will include a total of 8 visits to the CAMH Russell site (screening, training, baselines, week 1-4, follow-up). Participants should be between the ages of 18-60, meet criteria for CUD (moderate to severe), meet criteria for Bipolar Disorder, be on a stable dose of mood stabilizing medication(s), and be non-treatment seeking cannabis user. The visits will take up a total of approximately 22.5 hours with compensation for time provided for both groups. These visits will involve multiple clinical, substance use, and cognitive assessments. Abstinence will be maintained by weekly behavioural coaching sessions and contingency reinforcement for the CR group.

Inclusion Criteria:

• All participants must be between the ages 18-60
• Meet SCID for DSM-5 diagnostic criteria for cannabis use disorder, moderate to severe
• Meet SCID for DSM-5 diagnostic criteria for Bipolar Disorder (Type I or II)
• Be an outpatient receiving a stable dose of mood stabilizing medication(s) for at least one month
• Have a Hamilton Depression Rating Scale (HDRS-17) baseline assessment in the range of 12-25
• Have a Full-Scale IQ of at least 80 as determined by the WTAR
• Be a non-treatment seeking cannabis user
• Evidence of sufficient motivation and effort as measured by a Test of Memory Malingering (TOMM) score of at least 45
• Y-MRS baseline score in the range of 0-15

Exclusion Criteria:

• Meets criteria for abuse or dependence of alcohol or other illicit substances within the past 6 months (with the exception of cannabis, nicotine, or caffeine)
• Positive urine screen for illicit substances other than cannabis, nicotine, or caffeine
• Current suicidal or homicidal ideation
• Psychotic disorder diagnosis (e.g. schizoaffective disorder, major depression with psychotic features) as determined by the SCID
• Treatment seeking for cannabis use
• Head Injury > 5 minutes LOC
• Exceed upper and lower cut-offs on HSRD-17 and YMRS