Pilot Trial of Contingency Management for Long-Term Cannabis Abstinence

Inclusion Criteria: * Male and female adolescents actively enrolled in a middle or high school in the Boston area who are between the ages of 13 and 19 (inclusive); * Average use of cannabis at least 3 times per week during the 3 months prior to study enrollment; * Cannabis use reported within 7 days of study enrollment; * No immediate plan to discontinue cannabis use; * Have a parent or legal guardian who is competent and willing to provide written informed consent for the active study phase (if under the age of 18); * Competent and willing to provide written informed assent for the active study phase (if under the age of 18); * Competent and willing to provide written informed consent (if age 18 or older); * Able to communicate in English language; * Have a parent/guardian who can communicate in English language; * Able to commit to 27 study visits in approximately 6 months; * Able to safely participate in the protocol and appropriate for outpatient level of care, in the opinion of the investigator. Exclusion Criteria: \- Any severe developmental delays (including, but not limited to, Autism Spectrum Disorder, Intellectual Disability, and Down Syndrome).