Co-morbidity between posttraumatic stress disorder (PTSD) and substance use disorders (SUD) is high and there is a need for empirically validated treatments designed to address PTSD among SUD patients. One effective PTSD treatment that may be useful in treating PTSD-SUD is exposure therapy. This paper reviews the relationship between comorbid PTSD and SUD, the basics of exposure therapy for PTSD, and reviews preliminary work assessing the utility, safety, and tolerability of exposure therapy for PTSD-SUD. Although more research is needed, preliminary studies suggest that exposure therapy for PTSD-SUD is safe and tolerable and shows promise as an efficacious treatment.
Key Words: PTSD, Posttraumatic Stress disorder, Substance Use Disorder, Exposure Therapy, Comorbidity, Alcoholism, Drug Abuse.
Substance abuse among individuals with co-occurring mental disorders has been a topic of concern with regards to prevalence, diagnostic considerations, treatment, and relapse. The presence of substance use disorders (SUDs) generally complicates treatment of both the SUD and the comorbid condition, and has been linked to poorer prognosis overall (Grant et al., 2004; O'Brien et al., 2004; Ouimette, Finney, & Moos, 1999). The present paper will focus on one of the most common comorbidities, the co-occurrence of posttraumatic stress disorder (PTSD) and SUDs. This paper will briefly describe the prevalence of PTSD-SUD comorbidity, potential mechanisms that may help explain the high comorbidity, and will present preliminary evidence to support the use of trauma-focused exposure therapy to treat co-occurring PTSD and SUD.
Chilcoat and Menard (2003) summarized the prevalence estimates of trauma exposure, PTSD, and comorbid SUDs from multiple epidemiological studies, including the most widely cited comorbidity studies, the Epidemiologic Catchment Area Study (ECA; Helzer, Robins, & McEvoy, 1987) and the National Comorbidity Study (NCS; Kessler, Sonnega, Bromet, Hughes, & Nelson, 1995). Lifetime prevalence for PTSD across the cross-sectional studies ranged from 1-7.8%. Comorbidity between PTSD and SUD was compared using odds ratios (ORs). ORs ranged from 1.56-8.8 dependent on SUD diagnosis type (across studies, alcohol dependence had lower ORs than other drug dependence diagnoses), indicating substantially increased odds of a SUD among those with a PTSD diagnosis versus those without (Chilcoat & Menard, 2003). This pattern was upheld when comparing SUDs in those with trauma exposure versus no exposure, but was somewhat attenuated in comparison to the PTSD statistics. Results from a large prospective study indicated a substantially increased risk (four times higher) of developing SUDs among those with PTSD versus those without the disorder (Chilcoat & Breslau, 1998).
In clinical samples, a large portion (11-60%) of individuals seeking treatment for SUDs meet diagnostic criteria for PTSD (Brady, 2001; Dansky et al., 1996; Grice, Brady, Dustan, Malcolm, & Kilpatrick, 1995; Jacobsen, Southwick, & Kosten, 2001; Najavits et al., 2003; Triffleman, Marmar, Delucchi, & Ronfeldt, 1995). As with epidemiological studies, methodological differences between studies can contribute to the variability of estimates (Chilcoat & Menard, 2003). Another possible explanation of the wide discrepancy between studies reporting rates of PTSD in SUD samples is the PTSD symptom changes seen over time in this population. While it has been hypothesized based on clinical observations that PTSD symptoms may worsen during abstinence (e.g., Najavits, 2005), a recent empirical study provides evidence of the opposite (Coffey, Schumacher, Brady, & Dansky Cotton, in press). Individuals with a history of trauma and dependent on cocaine and alcohol were assessed over 28-days of monitored abstinence (n=162). Twenty-eight percent of the sample met current criteria for PTSD. …