Teen brain scans reveal what happens when cannabis stops

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Male and female adolescents between the ages of 15 and 18 (inclusive). * Have a parent or legal guardian who is able and willing to provide written informed consent. * Competent and willing to provide written informed assent (participants \<18) or consent (participants=18). * Native English speaker. * Have a parent or legal guardian who is fluent in English. * Able to commit to 9 study visits in approximately 60 days (6 weeks). * Able to safely participate in the protocol and appropriate for outpatient level of care, in the opinion of the PI. * No active psychosis or current use of antipsychotic medications. * Participants taking psychotropic medications will be included if the medications have been stable for 6 weeks and are expected to remain stable for the duration of their study participation (i.e., through the third MRI). * For CB-Abst (n=24) and CB-Mon (n=20) groups: at least 5 days of use per week on average in the past two months and meet DSM-V cannabis use disorder (CUD; at least Mild) criteria. Cannabis use reported within seven days of baseline visit. Positive qualitative urine toxicology test at baseline for THC. No immediate plan to discontinue cannabis use. * For Con (n=20): no lifetime history of cannabis use. Negative qualitative urine toxicology test at baseline for THC. No immediate plans to begin cannabis use. * For optional components (A: daily remote assessments during and/or (B) after treatment period): access to a personal device (e.g., smartphone or computer) on which to complete daily remote assessments. Exclusion Criteria: * Past twelve-month history of substance use disorders (except for Cannabis Use Disorder in CB-Abst and CB-Mon), assessed via semi-structured psychodiagnostics interview at baseline. * Contraindications for MRI (ascertained via participant and parent report), including but not limited to: 1. Metal implants such as surgical clips or pacemakers, or history of working with metal, unless the possibility of a metal fragment can be ruled out by recent orbital scans. 2. Prior head trauma with neurological sequelae. 3. Claustrophobia. 4. Weight incompatible with MRI safety. 5. Pregnancy. * Previous or current diagnosis of psychosis, cognitive disability, or bipolar disorder. * Active suicidality. * Taking a psychotropic medication that has not reached stability criterion (same medication type and dose for 6 weeks with no planned changes over the study period). * Any other medical or psychiatric condition deemed serious or contraindicated for any study procedures by Dr. Tervo-Clemmens.