The primary outcome will be changes in alcohol use assessed by Ehyl glucuronide immunoassay urine-tests, breath-tests, as well as self- and clinician-reported alcohol use. The secondary outcome will be changes in intensive outpatient group attendance assessed by intensive outpatient clinician-report, as well as administrative data sources, and self-report. Other outcomes will include: urine-tests and self-reported illicit drug use, psychiatric symptoms, other outpatient treatment utilization, HIV-risk, and nicotine use. All outcomes will be assessed [for 4-weeks prior to study enrollment (self-report, clinician ratings etc)] and throughout the 4-week induction, 12-week intervention, and 3-month follow-up periods.