In the U.S. suicide is the fourth leading cause of death in adults between 18 and 65. There is a link between drug problems and an increased risk of suicide but the specific risk factors among drug users are poorly understood. A team of researchers from the Ann Arbor Department of Veterans Affairs compared 854 drug users who killed themselves between 2002 and 2006 and 4,228 drug users who didn't. Of those people who killed themselves 70% did so by violent means such as shooting or hanging themselves or jumping off a tall building. Diagnoses of depression, anxiety, bipolar disorder and post-traumatic stress disorder (PTSD) were all associated with an increased risk of violent and non-violent (e.g. taking a deliberate overdose, gassing oneself) suicide. People who took drugs from the opium family or who took more than one kind of drug were more likely to kill themselves in a non-violent fashion.
Ilgen, Mark A. ... [et al] - Violent and nonviolent suicide in veterans with substance-use disorders Journal of Studies on Alcohol and Drugs July 2010, 71(4), 473-479