Cannabis Effects on Sleep, Circadian Rhythms, and Light Sensitivity in Young Adults

Significant or unstable acute or chronic medical conditions. Examples of such conditions include, but are not limited to, central nervous system disorders (e.g., head injury, seizure disorder, multiple sclerosis, tumor), cardiovascular or hemodynamically significant cardiac disease, liver disease (e.g., acute or chronic hepatitis, hepatic insufficiency), migraine or chronic headaches, active peptic ulcer disease, inflammatory bowel disease, renal failure, arthritis, and diabetes and other endocrine disorders. Seizure disorder in particular will be exclusionary due to the increased risk it confers for cannabis withdrawal symptoms. Eye/retinal conditions such as diabetic retinopathy or glaucoma will be exclusionary, although should be very rare in this population. Individuals with well-controlled health conditions that do not affect sleep, retinal function, and/or well-being (e.g., well-controlled thyroid disorders, asthma, or ulcer) will not be excluded. To evaluate these criteria, potential participants will complete a locally-developed Medical History Questionnaire.

Past or current DSM-5 bipolar disorder or psychotic disorders. Psychiatric disorders will be evaluated using the Mini International Neuropsychiatric Interview (MINI) and the WHO-DAS 2.0, supplemented by clinical interview. We will not exclude participants for subsyndromal symptoms or disorders in these domains. We will not exclude participants for other psychiatric disorders, particularly given the high comorbidity between cannabis use disorder and major depression and anxiety disorder, as long as severity is in the moderate range or lower based on the WHO-DAS 2.0 (average score <4).

Daily use of alcohol; regular use of illicit substances. Regular use (as defined above) of illicit substances other than cannabis over the past 3 months will be exclusionary. Substance use will be assessed using the Timeline Follow Back method, as well as a urine drug screen.

Past or current substance use disorders other than cannabis use disorder, nicotine use disorder, and mild alcohol use disorder (moderate and severe alcohol use disorder are exclusionary).