In the current study, drug use and dependence were not exclusionary criteria and community-based participants were recruited regardless of substance dependence. This is a unique study design and its purpose is to allow us to better compare cocaine dependent cases with individuals from their communities. Large scale nationally representative studies can compare cocaine dependent participants and non-dependent individuals; however, comparisons of participants within neighborhoods are not possible. By contrasting participants from the same neighborhoods, we may reduce or eliminate the influence of unmeasured neighborhood environmental features on the relationship between cocaine dependence, traumatic events, and PTSD.
