Psychiatric comorbidity and suicidality among intravenous drug users

Background: Prevalence of lifetime psychiatric comorbidity and history of attempted suicide among intravenous drug users was investigated. Method: One thousand sixty-two relatives of hospitalized alcoholics, felons, and control subjects were administered a structured interview that gathered data on lifetime psychiatric symptoms and psychoactive drug use. Psychiatric diagnoses were based on interview information, medical records, and family history data. Comparisons were made between 411 subjects who used no illicit drugs, 329 cannabis users, 230 subjects who had used psychoactive drugs other than cannabis more than five times but had never injected drugs, and 92 intravenous drug users. Results: Any history of injecting drugs increased the odds of being diagnosed with antisocial personality disorder by a factor of 21.01, alcoholism by 4.42, and unipolar depression by 3.02. A diagnosis of antisocial personality disorder increased the odds of having injected drugs by a factor of 27.19, while diagnoses of alcoholism or unipolar depression conveyed odds for injecting drugs of 4.62 and 3.70, respectively. Intravenous drug use was associated with an 8.27-fold increase in odds for a suicide attempt compared with no drug use. Conclusion: Rates of alcoholism, depression, and antisocial personality disorder, but not other psychiatric disorders (other than drug dependence), are significantly elevated in intravenous drug users. Moreover, among drug users, the decision to inject is differentially made by those with antisocial personality disorder. A history of suicide attempt is common among intravenous drug users, but injecting appears to convey little additional risk above substantial but non- intravenous drug use.