Integrated vs Sequential Treatment for PTSD and Addiction

Inclusion Criteria: * Male or female Persian Gulf Era veterans between 18-65 years old. Older individuals are unlikely to have served in Iraq or Afghanistan. * Current diagnosis of PTSD (symptom duration \> 3 months) with clinically significant trauma-related symptoms, as indicated by a score of at least 50 on the PCL * Current abuse or dependence on alcohol, stimulants such as cocaine, opioids, including prescription opioids or benzodiazepines. Subjects must report using on average at least 10 out of 30 days prior to signing consent. Of note: subjects can be abusing or dependent upon nicotine or marijuana but these will not be considered sufficient for inclusion * Provides informed consent * Speaks and reads English Exclusion Criteria: * Current suicidal or homicidal ideation with intent and/or plan that, in the judgment of the investigator, should be the focus of treatment * Meets current DSM-IV criteria for bipolar affective disorder, schizophrenia or any psychotic disorder * Has unstable or serious medical illness, including history of stroke, seizure disorder, or unstable cardiac disease * History of moderate or severe traumatic brain injury (TBI) * Participation in Prolonged Exposure Therapy in the last 6 months. * Initiation of a new psychotherapy program in the last 2 months. * Active participation in a formal addiction treatment program. Actively engaged is defined as any visit in the program in the prior month and pending future appointments for the treatment of addictions * Change in psychotropic medication in the 1 month prior to treatment except for the use of oxazepam for alcohol detoxification or a taper of a previously used benzodiazepine. * Therapeutic use of a benzodiazepine greater than the equivalent of more than 40 mg of diazepam (see chart) at the time of randomization.