Dissociative psychopathology among opioid use disorder patients: exploring the “chemical dissociation” hypothesis Eli Somer a, ⁎ , Libby Altus a , Karni Ginzburg b a School of Social Work, University of Haifa, Haifa 31905, Israel b School of Social Work, University of Tel Aviv, Tel Aviv 69978, Israel Abstract Background: Although early trauma is a well-recognized risk factor for both dissociation and substance abuse, there are inconsistent reports on the association between substance abuse and dissociation. This inconsistency may be resolved by the “chemical dissociation” hypothesis that suggests that some substance abuse patients may not exhibit high levels of dissociation, despite their trauma history, because they may achieve dissociative-like states through chemicals consumption. This article describes 2 studies aimed to (a) assess the incidence of dissociative psychopathology among recovering opioid use disorder (OUD) patients and (b) examine the chemical dissociation hypothesis. Methods: One hundred forty-nine patients receiving treatment in a heroin recovery program and 46 controls were administered self-report measures of dissociation and childhood maltreatment in study 1. A similar battery and an assessment of addiction severity were completed by 50 methadone maintenance treatment (MMT) patients and 30 detoxified OUD patients in study 2. In addition, Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Dissociative Disorders–Revised was administered to a subsample of MMT and detoxified OUD patients. Results: Patients with OUD reported higher levels of child maltreatment and dissociation than controls. Although MMT and detoxified patients did not differ in severity of addiction and child maltreatment, detoxified outpatients had higher levels of dissociation than MMT outpatients: 23% of the detoxified patients and 12% of the MMT patients were diagnosed with a dissociative disorder. Conclusions: These findings support the chemical dissociation hypothesis of OUD and suggest that detoxification programs should take into consideration the high incidence of comorbid dissociative disorders among their recovering OUD patients. © 2010 Elsevier Inc. All rights reserved. 1. Introduction Dissociative disorders (DDs) and opioid use disorder (OUD) are thought to be related problems. Trauma history, particularly childhood trauma, seems to be an etiological factor in both [1]. That is, although early trauma is a well- recognized risk factor for dissociation (eg, [2,3]), a growing body of data provide evidence for its contribution to substance abuse. Accordingly, studies indicate that people with a childhood trauma history constitute a significant proportion of opioid users [4], severity of substance abuse is positively associated with severity of child abuse [5], and recovering OUD patients report higher levels of traumatiza- tion compared with non–OUD outpatients [6-8]. Somer [1] posited that OUD might be the second stage of a strategy developed for coping with intolerable experiences and their memories when psychologic coping fails, when a rapid and efficient relief in posttraumatic pain is sought, and when substances are available. That is, when psychologic dissoci- ation is ineffective, or when substances that are effectively able to produce immediate numbing are available, trauma- tized persons may look beyond their own mental resources for relief; when these victims get access to consciousness- altering substances, they may discover the immediate advantages of “chemical dissociation” and its rapid effect on both the body and the mind [7]. This is when chemical dissociation can become a self-medicating alternative. Reports on the association between substance abuse and dissociation are less conclusive. On the one hand, there are Available online at www.sciencedirect.com Comprehensive Psychiatry 51 (2010) 419 – 425 www.elsevier.com/locate/comppsych Study 1 was supported by a grant from the Israel Anti-Drug Authority. ⁎ Corresponding author. E-mail address: somer@research.haifa.ac.il (E. Somer). 0010-440X/$ – see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.comppsych.2009.09.007