The aim of this research is to assess whether Contingency Management is effective in improving treatment adherence in substance use disordered (SUD) patients with comorbid PTSD. Although Prolonged Exposure therapy (PE) is the gold standard treatment for PTSD, the few studies of this treatment in substance users have shown poor adherence. Contingency Management is a well-established approach that could be used to enhance adherence to PE. From a consented sample of 125 opioid-dependent and methadone-treated patients at Addiction Treatment Services, an intent-to-treat sample of 62 patients with co-occurring current PTSD will be offered PE. Half of the 62 participants will be randomly assigned to a Prolonged Exposure with Contingency Management (PE+CM) condition that provides monetary-based incentives for attending the PE therapy sessions. The comparison condition will be assigned to a Prolonged Exposure (PE) condition without the attendance incentives intervention. The PE sessions will be scheduled once per week for 12 weeks, with a 12-week follow-up. Groups will be compared primarily on adherence to the PE schedule, improvement in PTSD symptoms, and rates of drug use (urine specimens, self-reported use). The study's three primary aims are to 1) Evaluate the efficacy of adding voucher-based attendance incentives to PE for PTSD to increase adherence in SUD patients in a methadone treatment program; 2) Evaluate the efficacy of adding voucher-based attendance incentives to PE for PTSD to reduce PTSD symptoms in SUD patients; and 3) Evaluate the effect of PE for PTSD on rates of drug use in SUD patients.

Inclusion Criteria for Phase I (evaluation):

• positive screen for PTSD, as determined by score on the MPSS-R
• methadone maintenance for at least 4 weeks (to help ensure initial stabilization on methadone)
• at least 18 years of age

Inclusion criteria for Phase 2 (treatment):

• confirmation of current PTSD based on the Clinician-Administered PTSD Scale
• no psychiatric contraindications to PE (e.g., current suicidal/homicidal intent)
• clear memory for the traumatic event (e.g., flashbacks or re-experiencing the event)
• interest in receiving PE
• agree to sign release of information for any current psychiatric treatment providers outside of ATS
• agree to delay taking daily methadone dose on exposure therapy days until after session
• no history of prior exposure-based therapy for PTSD
• agree to audiotaping of therapy sessions

Exclusion Criteria:

• pregnancy
• acute medical problem that requires immediate and intense medical management (e.g., AIDS defining illness; active tuberculosis)
• presence of a formal thought disorder, delusions, hallucinations, or imminent risk of harm to self or others