Exposure to trauma: a comparison of cocaine-dependent cases and a community-matched sample

The purpose of this study was to examine rates of traumatic events and PTSD in cocaine-dependent cases and a community comparison sample.

Participants were interviewed as part of the Family Study of Cocaine Dependence. A cross-sectional case-cohort design assessed a total of 918 participants: 459 cocaine-dependent cases recruited from chemical dependency treatment and 459 community-based participants. Community-based comparison participants were matched to cocaine-dependent cases on year of birth (within 1 year), ethnicity, gender, and neighborhood (zip code). Participants completed a personal interview modeled after the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA).

Compared to community-based individuals, cocaine-dependent cases recruited from treatment experienced higher rates of assaultive events including rape or sexual assault in women (58% vs. 33%) and threatened with a weapon in men (75% vs. 52%). Cocaine-dependent cases endured significantly more types of trauma than the community-based participants (4.64 vs. 3.08) and PTSD (22.4% and 12.2%). The number of traumatic exposures, witnessing trauma to others, experiencing violent trauma, and being female were predictive of conditional risk of PTSD, even after controlling for cocaine dependence and other demographic factors.

Cocaine dependence is strongly associated with an increased risk of exposure to traumatic events and PTSD, and experiencing multiple, violent traumas increases the risk of PTSD, regardless of cocaine dependence. The high prevalence of trauma seen in our community-based participants emphasizes the role of violence in the neighborhood and the connection between drug dependence, trauma exposure, and PTSD.