The experimental design consists of three treatment stages and a follow-up phase. Stage I (12 weeks) is a four-group randomized comparison of four treatments: antidepressant medication alone (Fluoxetine); psychotherapy alone (CBT); a combination of the medication and psychotherapy (Comb); and a placebo control medication condition (Pbo). Stage II (six weeks) is a treatment consolidation phase in which we ask whether longer treatment in responders and higher intensity treatment in partial responders to their Stage I treatment would be helpful. Non-responders at the end of Stage I will be referred to open community treatment, or for ethical and practical reasons in the case of non-responders to Placebo, to open treatment of their choice with one of the three active study treatments administered by the study team. Responders at the end of Stage I advance to 6 weeks of maintenance treatment in their assigned arm. Partial responders to CBT receive an additional 6 weeks of CBT in their assigned arm; partial responders to Fluoxetine may receive a higher dose for six weeks. Partial responders to the Comb treatment will receive an additional 6 weeks of CBT and may receive a higher dose of medication for six weeks. Stage III (18 weeks) is a treatment maintenance phase for those teenagers who have continued to respond well. Treatment will be continued and progress will be monitored. Stage IV (one year) is an assessment-only follow-up phase to help us understand the long-term benefits of the treatments.