Suicide attempts in high-dose benzodiazepine users.

Substance use disorders are associated with increased suicidal behavior. The suicidal behavior in patients without a history of illegal substance abuse, who consume benzodiazepines (BZDs) regularly in doses higher than those recommended, has not been previously studied. The aim of this study was to investigate the factors associated with the past history of suicide attempts in high-dose regular BZD users (HDRUs). Fifty-five HDRUs were recruited from inpatient and outpatient psychiatric services, and were compared to 55 psychiatric controls, matched for demographic characteristics and psychiatric diagnoses to HDRUs (Controls A), and to 55 psychiatric controls matched only for demographic characteristics to HDRUs (Controls B). Both control groups were non-BZD users. Patients with previous or current use of illegal substances were excluded. There was a statistically significant difference in the history of suicide attempts, comparing HDRUs (17 attempters, 30.9%) with Controls B (two attempters, 3.6%), while the difference was not significant comparing HDRUs with Controls A (10 attempters, 18.2%). Using logistic regression analysis, it was found that only comorbid borderline personality disorder (BPD), not high-dose BZD use, was independently associated with a history of suicide attempt. The percentage of patients with a history of suicide attempt was significantly higher in HDRUs with comorbid BPD, compared to HDRUs without BPD.