Do treatment improvements in PTSD severity affect substance use outcomes? A secondary analysis from a randomized clinical trial in NIDA’s Clinical Trials Network.
This secondary analysis examines the temporal course of improvement in symptoms of posttraumatic stress disorder (PTSD) and substance use disorder among women in outpatient substance abuse treatment. Participants included 353 women participating in protocol CTN-0015, randomly assigned to 12 sessions of either trauma-focused or health education group treatment. PTSD and substance use assessments were conducted during treatment and posttreatment at 1 week and after 3, 6, and 12 months. A continuous Markov model was fit on four defined response categories (nonresponse, substance use response, PTSD response, or global response [improvement in both PTSD and substance use]) to investigate the temporal association between improvement in PTSD and substance use symptom severity during the study’s treatment phase. A generalized linear model was applied to test this relationship over the follow-up period. Results found that subjects exhibiting nonresponse, substance use response, or global response tended to maintain original classification; and subjects exhibiting PTSD response were significantly more likely to transition to global response over time, indicating maintained PTSD improvement was associated with subsequent substance use improvement. Trauma-focused treatment was significantly more effective than health education in achieving substance use improvement, but only among those who were heavy substance users at baseline achieved significant PTSD reductions. In conclusion, PTSD severity reductions were more likely to be associated with substance use improvement, with minimal evidence of substance use symptom reduction improving PTSD symptoms. Results support the self-medication model of coping with PTSD symptoms and an empirical basis for integrated interventions for improved substance use outcomes in patients with severe symptoms.
An editorial about this paper was included in the same issue of American Journal of Psychiatry. Back, Sudie E. Toward an improved model of treating co-occurring PTSD and substance use disorders. American Journal of Psychiatry 2010;167(1):11-13.
Related protocols: CTN-0015