Neural and Psychiatric Consequences of Cannabis Use in Adolescents

Cannabis users: To capture a wide range of cannabis use frequency, meeting DSM-5 criteria for cannabis use disorder will not be required. However, in order to ensure sufficient exposure, we will require majority of adolescents with cannabis use to have a significant cannabis use (self-reported use on more or equal to 10 of the prior 30 days and positive THC urine toxicology).

Depression: Similarly, to capture a wide range of depression illness severity, we will allow participants with subthreshold depression, defined as a raw severity score of >=30 on the Children's Depression Rating Scale-Revised (CDRS-R, for ages 14-17) and as a raw severity score of >=12 on the Montgomery Asberg Depression Rating Scale (MADRS, for ages 18-20). However, we plan for at least 50% of participants with depressive symptoms to have a raw severity score of >=40 on the CDRS-R and of >=20 MADRS, which are considered reliable for depression. Additionally, we will allow participants with a research diagnosis of Major Depressive Disorder as defined by the MINI, even with a CDRS-R score below 30 or a MADRS score below 12. Moreover, because there could be individuals without MDD who have current depressive symptoms, individuals who lack a diagnosis of a depressive disorder but have a CDRS-R score of 30 (or higher) or a MADRS score of 12 (or higher) will be allowed. Through careful recruitment, we will ensure distributions of depression severity. Based on our prior studies employing similar criteria, we anticipate that anhedonia, anxiety and depression severity scores will be normally distributed in our samples.