Both pharmacotherapeutic and psychosocial interventions have domenstrated efficacy for PTSD. However, although these interventions can be helpful, many patients remain symptomatic despite initial treatment. In this study, we will examine the relative efficacy of the addition of paroxetine-CR compared to placebo for patients remaining symptomatic despite a brief and intensive course of cognitive-behavioral therapy (CBT).

This is a systematic controlled study examining the use of augmentation with pharmaotherapy for PTSD patients remaining symptomatic despite CBT (exposure therapy). The aims of the study include examination of: (1) the efficacy of paroxetine-CR compared to placebo as additions to ongoing exposure therapy in patients who failed to respond to brief, intensive CBT; (2) the tolerability of paroxetine-CR compared to placebo as additions to ongoing exposure therapy in patients who failed to respond to brief, intensive CBT; (3) the outcome of patients at 6 months follow-up to randomized treatment. Patients will initially have intensive (8 sessions over 4 weeks) prolonged exposure therapy. Patients who remain symptomatic will be randomzied to receive either flexibly-dosed paroxetine-CR (12.5 mg/d - 62.5 mg/d) or placebo in conjunction with additional 5 sessions of prolonged exposure over 10 weeks.

Inclusion Criteria:

• Male or female outpatients at least 18 years of age with a primary (the condition that is most central to the patient's current distress) psychiatric diagnosis of PTSD as defined by DSM-IV criteria
• Patients must have remained symptomatic (CGI-S > or = 3) and a score of at least 6 on the SPRINT after a minimum of 7 sessions of prolonged exposure (delivered within 6 weeks) to be eligible for randomized treatment.

Exclusion Criteria:

• Serious medical illness or instability for which hospitalization may be likely within the next 3 months
• Pregnant or lactating women or those of childbearing potential not using medically accepted forms of contraception
• Concurrent use of other psychotropic medications
• Lifetime diagnosis of schizophrenia or any other psychotic disorder, mental retardation, organic mental disorders, or bipolar disorder
• Obsessive-Compulsive Disorder, eating disorders, or alcohol/substance abuse disorders within the last 6 months
• A current primary diagnosis of major depression, dysthymia, social anxiety disorder, and generalized anxiety disorder
• A history of hypersensitivity or poor response to paroxetine or those using antidepressants, buspirone, or beta-blockers within 2 weeks of randomization
• Concurrent dynamic or supportive psychotherapy if started within 2 months prior to onset of study entry