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.