This study will examine whether interpersonal psychotherapy is as effective in treating post-traumatic stress disorder as the established therapies of prolonged exposure and relaxation.

Post-traumatic stress disorder (PTSD) is caused by a traumatic experience often involving physical harm or the threat of harm or death. The emotional numbness and traumatic flashbacks symptomatic of PTSD interfere with everyday life for approximately 7.7 million adults. Besides prescription drug treatment, only exposure-based therapies, like prolonged exposure (PE) therapy, have been proved effective in treating PTSD. Interpersonal psychotherapy (IPT), which is not based on exposure, is effective in treating mood disorders, and pilot studies indicate it may also be effective in treating PTSD. IPT treats patients by helping them to improve their interpersonal functioning, as opposed to PE, which helps patients by guiding them to recreate traumatic memories in safe circumstances. This study will determine whether IPT is as effective as PE, the gold standard, in treating PTSD. Relaxation therapy, a commonly used control therapy for studies of PTSD, will be used for that purpose here.

All participants will be screened for PTSD, with those meeting the criteria being randomly assigned to one of the following three treatment groups:

• Group 1 participants will receive IPT. They will meet weekly for fourteen 50-minute sessions focusing on interpersonal consequences of the trauma affecting them and their relationships with others.
• Group 2 participants will receive PE. They will meet for 10, unevenly spaced 90-minute sessions during which they will face the trauma responsible for their symptoms.
• Group 3 participants will receive relaxation therapy. They will meet for nine 90-minute sessions and one 30-minute session during which they will learn relaxation methods.

All treatments will last 14 weeks, with assessments made by mental health professionals at screening, the midpoint of the study, the end of the study, and a 3-month follow-up. PTSD symptoms will be assessed through clinical interviews and self-report measures. In addition, participants will complete other interviews and tests that will examine a variety of factors relating to mental health, including comorbidity of other conditions, affect, social functioning, and quality of life.

• Behavioral: Interpersonal Psychotherapy
• Behavioral: Prolonged Exposure Therapy
• Behavioral: Relaxation Therapy

• Experimental: Participants will receive interpersonal psychotherapy.
• Active Comparator: Participants will receive prolonged exposure therapy.
• Active Comparator: Participants will receive relaxation therapy.

• Bleiberg KL, Markowitz JC. A pilot study of interpersonal psychotherapy for posttraumatic stress disorder. Am J Psychiatry. 2005 Jan;162(1):181-3.
• Markowitz JC, Bleiberg KL, Christos P, Levitan E. Solving interpersonal problems correlates with symptom improvement in interpersonal psychotherapy: preliminary findings. J Nerv Ment Dis. 2006 Jan;194(1):15-20.
• Taylor S, Thordarson DS, Maxfield L, Fedoroff IC, Lovell K, Ogrodniczuk J. Comparative efficacy, speed, and adverse effects of three PTSD treatments: exposure therapy, EMDR, and relaxation training. J Consult Clin Psychol. 2003 Apr;71(2):330-8.

Inclusion Criteria:

• Meets DSM-IV criteria for primary, chronic PTSD
• At least moderately severe symptoms, defined by a minimum total (frequency plus severity) Clinician-Administered PTSD Scale score greater than 50
• Willing to undergo an independent clinical assessment and other ratings

Exclusion Criteria:

• Diagnosis of schizophrenia, bipolar disorder, or other psychotic disorders
• Psychiatric disorder due to a general medical condition
• Current substance abuse or dependence
• Acute suicide or homicide risk
• Unstable or life-threatening medical condition
• Primary diagnosis of borderline personality disorder, major depressive disorder, or major depression, melancholic subtype
• Diagnosis of antisocial personality disorder
• At least partial benefit from current treatment regimen
• Unwillingness to discontinue current ineffective psycho- or pharmacotherapy
• Inability to speak or read English