The specific aims of this study are:

1. To compare the effectiveness of a cognitive behavioral therapy (prolonged exposure, PE) to that of PE and medication (sertraline).
2. To compare the durability of PE gains to that of PE and sertraline at 3, 6, and 9 months post-treatment.
3. To compare those who have chosen their treatment to those who have not in terms of completion of treatment, treatment satisfaction, and short- and long-term effectiveness of the treatment.
4. To examine cost effectiveness of treatment delivery to trauma survivors with PTSD.

Exposure to traumatic events, such as automobile accidents and physical or sexual assault, can cause individuals to develop persistent psychological difficulties such as post-traumatic stress disorder (PTSD). PTSD is an anxiety disorder characterized by avoidance, hyperarousal symptoms, and mental re-experiencing of the traumatic event. PTSD is a serious condition that may cause social and psychological impairment; therefore, safe and effective treatments are needed. Both CBT (cognitive behavior therapy) and antidepressant therapy have been shown to effectively treat PTSD symptoms; however, comparisons of the treatments are limited. This study will compare the short- and long-term effectiveness of prolonged exposure and prolonged exposure plus the antidepressant sertraline.

Participants will either be randomly assigned to prolonged exposure (PE) or PE plus sertraline, or they will be able to choose one of the two treatments,which will be given for 10 weeks, followed by 9 months of follow-up assessments. Participants in the PE 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 PE plus sertraline group receive the same treatment as the PE group plus they will take sertraline daily for 10 weeks. These participants will be seen regularly 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 PE plus sertraline 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 9 months. Participants who do not respond to their assigned or chosen treatment will be offered booster sessions or 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, and 9 months after the study treatment period.

Inclusion Criteria:

• DSM-IV (Diagnostic & Statistical Manual of Mental Disorders) diagnosis of PTSD (with severity threshold)
• Experienced traumatic event at least 12 weeks prior to study entry
• Willingness to discontinue current CBT or antidepressant treatment if needed

Exclusion Criteria:

• Current diagnosis of schizophrenia or delusional disorder
• Medically unstable bipolar disorder, depression with psychotic features, or depression requiring immediate psychiatric treatment
• No clear trauma memory or trauma before age 3
• Current diagnosis of alcohol or substance dependence within 3 months prior to study entry
• Ongoing intimate relationship with the perpetrator of the traumatic event
• History of nonresponse to adequate trial of either CBT or sertraline
• Medical contraindication for sertraline
• Current high dose use of benzodiazepines
• Pregnant or sexually active female without adequate birth control