Towards a unitary perspective between Post-Traumatic Stress Disorder and Substance Use Disorder. Heroin use disorder as case study

Background Genetic, neurobiological, environmental and psychosocial mechanisms have received considerable attention in exploring the mechanisms that underlie comorbid PTSD and SUD. PTSD and SUD are not necessarily linked by a causal relationship, as the self-medication hypothesis had supposed. They might, in fact, both be caused by a third factor that predisposes these subjects to develop the two disorders (so allowing a unitary perspective). Methods Using a conceptualization of the PTSD spectrum, we studied the PTSD-SUD unitary perspective by testing the correlation between severity of heroin addiction, dose of opioid medication and severity of PTSD spectrum in 82 methadone-treated, heroin-dependent patients. Results Canonical correlation analysis (Wilks Lambda = 0.125 F = 1.41 p = 0.014), univariate and multivariate comparisons between subgroups, identified on the basis of addiction severity, showed a highly positive correlation between the PTSD spectrum and the severity of heroin addiction. In addition, negative correlations were found between PTSD spectrum severity and methadone dose (r = 0.225; p = 0.042). Conclusions This strength and breadth of the correlations encourage us to move towards a unified vision of the two disorders.