Trauma and PTSD in patients with alcohol, drug, or dual dependence: a multi-center study

Background:  We investigated (1) the prevalence of posttraumatic stress disorder (PTSD) in treatment-seeking subjects with substance use dependence (SUD), (2) the association between comorbid PTSD and the severity and course of addiction and psychopathology, and (3) this association in patients with subsyndromal PTSD, and in trauma exposure without PTSD.
Methods:  In this cross-sectional study, 459 subjects in 14 German addiction treatment centers participated with alcohol-dependence (A) in 39.7%, drug-dependence (D) in 33.6%, or both (AD) 26.8%. The diagnostic measures included the International Diagnostic Checklists (IDCL), Posttraumatic Diagnostic Scale (PDS), Addiction Severity Index (ASI), and the Brief Psychiatric Rating Scale (BPRS). Associations between independent characteristics and outcomes were analysed by univariate and multivariate statistics.
Results:  25.3% of the subjects had PTSD confirmed by both IDCL and PDS with higher rates in the AD (34.1%) and D (29.9%) groups compared with group A (15.4%, p  < 0.001). In 22.8%, PTSD was subsyndromal (either IDCL or PDS positive) without significant differences between SUD groups, and 18.3% met PTSD trauma criteria A without PTSD (exposure). After controlling for SUD and gender, trauma subgroups significantly differed regarding the onset of alcohol-related symptoms ( p  < 0.02), numbers of previous admissions ( p  < 0.03), severity of SUD ( p  < 0.001), current craving ( p  < 0.02), and psychopathology ( p  < 0.001). We observed the worst outcome in PTSD, while trauma exposure had no effects.
Conclusions:  The prevalence of PTSD is higher in drug than in alcohol dependence. The more strictly PTSD is diagnosed (by interviewer and questionnaire) the more clearly are associations with characteristics of SUD. PTSD seems to be an independent risk factor for an unfavorable outcome of SUD.