Cannabis, Linked Emotions, and Adolescent Risk Study

Inclusion Criteria: * Ages 12-18; * Current daily or near daily cannabis use (i.e., use ≥ 4 days per week on average; Timeline Followback); * Score ≥ 5 on PHQ-9; * Access to an internet-capable smartphone (iOS or Android); * Provision of at least 1 collateral contact for risk monitoring; * Provision of informed assent (or consent if 18 years or older) and parent/guardian consent if \<age 18; * Greater than 50% response rate to EMA prompts during the first EMA phase; * No immediate plan to discontinue cannabis use in the next 3 months; * Positive toxicology result for cannabis on baseline urinalysis. Exclusion Criteria: * Any factor that impairs ability to comprehend and effectively participate, including acute intoxication at time of consent; * Cannabis use \>4 times/day on average (to maximize likelihood of capturing mood and SI during non-use times); * Inability to speak/write English fluently; * Gross cognitive impairment, for example due to florid psychosis, intellectual disability, developmental delay, or neurodegenerative disease; * Current epilepsy diagnosis; * Individuals who are under the legal protection of the government or state (wards of the state); * Response of "No" to the knowledge check question regarding EMA suicidality response time; * Inability to wear Fitbit device.