The purpose of this study is to compare group-administered Cognitive Processing Therapy-Cognitive-only version (CPT-C), an evidence based treatment for posttraumatic stress disorder (PTSD), to Present Centered Therapy (PCT) in order to determine whether the results of CPT exceed those of receiving a therapy that focuses on current problems rather than past trauma in a group format.

Estimates indicate that between 100,000 and 300,000 Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) veterans are at significant risk for chronic post-traumatic stress disorder (PTSD), which can become a chronic disorder that impacts all areas of a person's life. PTSD treatment programs are being developed throughout the Department of Defense (DoD) and the Veterans Affairs (VA), but because of the large number of Service Members returning from deployment with PTSD, it is often necessary to provide psychotherapy in groups. Cognitive Processing Therapy (CPT), an evidence-based treatment for PTSD, was originally developed as a group-based intervention. However, group-based CPT treatment has never been systematically compared to other forms of group treatment. The public policy implications of the results of this trial are significant. If group treatment is found to be effective, then group treatment would be a more efficient and cost-effective therapy modality in most cases. The purpose of this study is to compare group-administered CPT-Cognitive-only version (CPT-C) to Present Centered Therapy (PCT) in order to determine whether the results of CPT exceed those of receiving a therapy that focuses on current problems rather than past trauma in a group format. One hundred (100) adult male and female active-duty OIF/OEF military personnel over 18 years of age will be enrolled into this study. Participants will be randomized to receive either group PCT or group CPT-C.

Inclusion Criteria:

• Adult male and female active duty, activated Reservist, or activated National Guard OIF/OEF military personnel or OIF/OEF veterans seeking treatment for PTSD
• diagnosis of PTSD determined by a clinician-administered Posttraumatic Stress Scale (PSSI)
• person has experienced a Criterion A event that is a specific combat-related event or high magnitude operational experience that occurred during a military deployment in support of OIF/OEF. The diagnosis of PTSD may be indexed to that event or to another Criterion A event.
• be over the age of 18
• speak and read English
• be stable on any psychotropic medications they may be taking.

Exclusion Criteria:

• current suicide or homicide risk meriting crisis intervention
• active psychosis
• moderate to severe brain damage (as determined by the inability to comprehend the baseline screening questionnaires)