The impact of alcohol use on the course of adolescent depression over one-year was investigated by following 197 consecutive adolescent outpatients with unipolar depression in a naturalistic treatment setting. Their baseline alcohol consumption was categorized in three groups: excessive use (defined as weekly drunkenness), regular use (monthly use, not weekly drunkenness), and no/occasional use (abstinence/less than monthly use). During the monthly BDI follow-up, the excessive users achieved remission less frequently, and after one year, had poorer psychosocial functioning than the no/occasional users. In conclusion, excessive alcohol use negatively affects the course of adolescent depression and psychosocial functioning. Weekly drunkenness seems to be of predictive value and this can be examined with a few simple questions. Means of reducing alcohol consumption among depressed adolescents are worth further investigations. (Contains 3 tables.)