Despite its importance as a public health concern, relatively little is known about the natural course of cannabis use disorders (CUDs). The primary objective of this research was to provide descriptive data on the onset, recovery and recurrence functions of CUDs during the high-risk periods of adolescence, emerging adulthood and young adulthood based on data from a large prospective community sample.

Probands (n = 816) from the Oregon Adolescent Depression Project (OADP) participated in four diagnostic assessments (T1–T4) between the ages of 16 and 30 years, during which current and past CUDs were assessed.

The weighted lifetime prevalence of CUDs was 19.1% with an average onset age of 18.6 years. Although gender was not significantly related to the age of initial CUD onset, men were more likely to be diagnosed with a lifetime CUD. Of those diagnosed with a CUD episode, 81.8% eventually achieved recovery during the study period. Women achieved recovery significantly more quickly than men. The recurrence rate (27.7%) was relatively modest, and most likely to occur within the first 36 months following the offset of the first CUD episode. CUD recurrence was uncommon after 72 months of remission and recovery.

CUDs are relatively common, affecting about one out of five persons in the OADP sample prior to the age of 30 years. Eventual recovery from index CUD episodes is the norm, although about 30% of those with a CUD exhibit a generally persistent pattern of problematic use extending 7 years or longer.

The clinical benefit for depression of an interactive computer-assisted cognitive-behavioral program on CD-ROM, the Wellness Workshop (WW), was evaluated in a randomized controlled trial.

A total of 191 individuals referred by primary-care physicians were randomly assigned to a control group, where physician-directed treatment as usual (TAU) was provided, or to a treatment group, where TAU was supplemented with the WW CD-ROM, delivered by mail (WW+TAU). Data were collected at baseline, at 6 weeks' post-intervention, and at a 6-month follow-up assessment. Participants were given a strong incentive by a reimbursement of $75 for completion of each assessment. Measures included symptom ratings obtained via structured clinical diagnostic interviews, as well as a battery of self-report questionnaires on symptoms specifically targeted by the intervention.

Analysis of results demonstrated evidence for skill acquisition for improving dysfunctional thinking and reducing anxiety. Among those who met diagnostic criteria for depression, WW+TAU participants were three times more likely to remit at 6 weeks' post-test than TAU participants.

The evidence supports the conclusion that the WW intervention added benefit to traditional care for depression. No placebo comparison group was included and the WW+TAU participants received slightly more attention (a supportive telephone contact, ⩽5 min from a psychologist 2 weeks after receiving the program). Overall, the findings add support to the accumulating evidence for the potential clinical benefit of computer-assisted behavioral health interventions.