Dissociation and substance abuse among people with PTSD: Results from the National Survey for Stress and Health in Japan.

Patients with posttraumatic stress disorder (PTSD) usually have other psychiatric comorbidities. This study analyzed data from a national survey in Japan (N = 1005 trauma-exposed adults) and examined co-occurring dissociation and substance abuse in patients with probable PTSD. Participants completed standardized screening measures of PTSD, dissociative symptoms, and substance abuse at baseline (T1), and then reported their levels of substance abuse again after 3 months (T2). Of participants who screened for PTSD at T1 (n = 639), 36.1 % reported dissociative symptoms, and 61.8 % reported substance abuse in the past two weeks. Participants with dissociative PTSD had significantly higher levels of substance abuse at both T1 and T2 than their non-dissociative counterparts. T1 dissociative symptoms significantly predicted T2 substance abuse (β =.075, p = .006). Dissociative symptoms also moderated the effects of T1 PTSD symptoms on T2 substance abuse. This study provides first data regarding the prevalence of dissociative symptoms and substance abuse among Japanese adults with PTSD. We also found that people with dissociative PTSD were more prone to subsequent substance abuse problems. Early screening for dissociative symptoms among people with PTSD is important. Future studies are needed to investigate the neural mechanisms behind dissociation and substance abuse.