onset of PTSD (Kessler et al.,1997a), and the odds of having alcohol use disorders increase with the number of PTSD criteria (Pietrzak et al., 2011). Furthermore, there is considerable overlap in the neural circuitry involved in addictions and the stress response and positive feedback loops provide mechanistic connections between stress and addictions (Cleck and Blendy, 2008; Kalivas and Volkow, 2005; Potenza et al., 2012; Sinha et al., 2005). Stress can modulate the initial rewarding effects of addictive drugs, reinstate drug seeking and cause relapse to substance use in individuals in recovery while substance use also alters the individual’s biologic response to stress (Brady and Sinha, 2005; Cleck and Blendy, 2008). Third, risk factors for the development of PTSD and AD overlap, including lower socioeconomic status and lower support from the spouse or partner, as found in our study as well as in clinical samples (Riggs et al., 2003). This overlap of risk factors may contribute to increased comorbidity directly or by potentiating the neural connections between stress and addictions. For example, lack of social support and resources could place individuals with single pathology (PTSD or AD) at greater risk for deterioration of the initial pathology and subsequent development of other
