Participants will either be randomly assigned to CBT or sertraline, or they will be able to choose one of the two treatments, which will be given for 10 weeks, followed by 24 months of follow-up assessments. Participants in the CBT group will have 10 weekly sessions of therapy. During the therapy sessions, participants will be encouraged to confront their general fears and the memory of their trauma through repeated storytelling. Participants will also be encouraged to practice the techniques learned in therapy in everyday life. Participants in the antidepressant group will take sertraline daily for 10 weeks. These participants will be seen weekly by a psychiatrist who will offer general encouragement and support, monitor response to medication, and record any side effects participants may be experiencing. The medication may be adjusted according to a dosing schedule and based on the study doctor's judgment. At the end of 10 weeks, participants in the antidepressant group will have the choice of either tapering the medication gradually to minimize the chance of withdrawal symptoms or staying on the medication for up to 24 months. Participants who do not respond to their assigned or chosen treatment will be offered the other treatment for 10 weeks. Self-report scales and questionnaires will be used to assess participants' PTSD symptoms, depression, anxiety, and social functioning. These assessments will occur at 3, 6, 12, and 24 months after the study treatment period.