 Depression is common in older adults, and antidepressant medication is only effective in about 60 of patients seeking treatment. The purpose of this study is to compare the effectiveness of two different augmentation strategies of antidepressant treatment for depressed older adults who have not responded to an adequate trial of antidepressant medication. The first augmentation strategy is Problem Solving Therapy PST, a 12-week psychotherapy treatment that has been shown to be effective in depressed older adults. The second augmentation strategy is medication augmentation, which will begin with six weeks of aripiprazole, an atypical antipsychotic medication that has also been shown to be effective in depressed older adults who have failed a trial of antidepressant medication. If patients have not remitted at the end of the 6 week aripiprazole trial, the aripiprazole will be stopped and they will be started on bupropion for the remaining 6 weeks of the study. Both aripiprazole augmentation and bupropion augmentation in depressed older adults have been approved by the FDA. No study has compared the effectiveness of PST and medication augmentation strategies for depressed older adults who are non-responders to an adequate trial of antidepressant medication in the current episode of their depression. 