There are well-established links between Post-Traumatic Stress Disorder (PTSD) and drug abuse. Among men who experience PTSD in their lifetime 52% develop alcohol problems and 35% develop drug problems and among women the rates are 28% and 27% respectively. Studies have consistently shown greater impairment on a wide variety of measures in those with PTSD and drug abuse compared to those with either problem alone. A study of 428 out-patients with cocaine addiction in the U.S. found that those people suffering from substance abuse and PTSD were more impaired to begin with and responded less well to treatment compared to those who did not have PTSD.
Najavits, Lisa M. ... [et al] - Six-month treatment outcomes of cocaine-dependent patients with and without PTSD in a multisite national trial Journal of Studies on Alcohol and Drugs May 2007, 68(3), 353-361