Compared with individuals with PTSD only, multiple indicators, including age of onset of PTSD and number of diagnostic criteria met, suggested that individuals with PTSD-AD had more severe PTSD than individuals with PTSD only. Compared with individuals with AD only, persons with PTSD-AD had greater number of AD criteria, were more likely to have impulsive behaviors, have difficulty expressing emotions, and used alcohol and drugs to relieve PTSD symptoms. Clinical studies have suggested that increased impulsivity (Roy, 2005; Zlotnick et al., 1997) and emotional dysregulation (van der Kolk and Fisler, 1994) may act as mediators of the trauma-related stress contributing to the development of substance use disorders. Community data also suggest a dynamic relationship between stress and impulsivity with regard to hazardous drinking (Fox et al., 2010). Targeting impulsivity and emotional regulation may help to achieve better outcomes for both PTSD and substance use disorders, as suggested by the Seeking Safety trials (Najavits, 1993; Norman et al., 2010; Ruglass et al., 2012).
