This multi-center study examined the prevalence of posttraumatic stress disorder (PTSD) and the level of dissociative symptoms in a German population of patients with different substance use disorders (SUD).

A total of 459 participants (59.7% male) were recruited in 14 study centers. Of these, 182 (39.7%) were alcohol dependent (A), 154 (33.6%) were drug-dependent (D), and 123 (26.8%) were dependent on both, alcohol and drugs (AD). Diagnostic measures included the Addiction Severity Index (ASI), the Childhood Trauma Questionnaire (CTQ), the Dissociative Experiences Scale (DES), and the Posttraumatic diagnostic scale (PDS). The International Diagnostic Checklists (IDCL) were used to confirm DSM-IV diagnoses of PTSD and SUD.

25.3% of the subjects had PTSD confirmed by both IDCL and PDS. Higher rates were found in the AD (34.1%) and D (29.9%) groups as compared to group A (15.4%, p < .001). Similarly, rates of dissociative symptoms as measured by the DES differed significantly between the different subgroups (AD: M=15.1±11.3; D: M=12.9±11.7; A: M=9.9±8.8; p < .001). In a stepwise linear regression model, childhood trauma severity was associated with dissociation independent from current PTSD. The relationships between SUD group and dissociation ceased to be statistically significant when age and gender were included in the model.

The findings support significant rates of PTSD and dissociative symptoms in patients with SUD and marked differences between the different SUD subgroups. The complex relationship between childhood trauma, dissociation, and PTSD in patients with SUD requires more research.