NDARC Technical Report No. 50 (1997)
The current study examined the prevalence of benzodiazepine dependence and psychopathology among heroin users in Sydney. Using the Composite International Diagnostic Interview (CIDI), 222 heroin users were assessed for lifetime and current drug dependencies, anxiety and depressive disorders. Benzodiazepines had been used by 91% of the sample, of whom 26% met the criteria for a lifetime diagnosis of dependence. Two thirds of the sample had used benzodiazepines in the preceding 12 months, of whom 22% received a current diagnosis of dependence.
Those subjects who were diagnosed as ever having been benzodiazepine dependent were significantly more likely than other subjects to have ever had an anxiety (75% v 55%) or depressive disorder (65% v 33%). In the majority of cases, the anxiety or depressive disorder preceded the onset of regular benzodiazepine use. While this suggests that, to some extent, heroin users who use benzodiazepines are self-medicating pre-existing psychopathology, it does not rule out the possibility that benzodiazepine use then gives rise to further anxiety and/or depression.
Heroin users with a history of benzodiazepine dependence had also been dependent on a greater number of drugs (excluding benzodiazepines) than the remainder of the sample. The Severity of Dependence Scale (SDS) was found to be an efficient measure of benzodiazepine dependence among the sample. An ROC analysis was performed, using DSM-III-R diagnoses of dependence as the criterion measure. The appropriate cut-off mark on the SDS was found to be 2, lower than that used when assessing heroin, cocaine or amphetamine dependence.
The high rate of benzodiazepine dependence among heroin users highlights the need for education for injecting drug users about the risk of benzodiazepine dependence, and the associated withdrawal syndrome. Doctors need to discuss these issues with their patients whenever they prescribe bezodiazepines, and should be mindful of the fact that heroin users who use benzodiazepines are at particularly high risk of becoming dependent. Regular use of benzodiazepines in conjunction with heroin also has serious implications for overdose.
Doctors should also be aware that many of the heroin users for whom they prescribe benzodiazepines are likely to have multiple drug dependencies, and co-existing anxiety and/or depressive disorders. Treatment services, such as methadone clinics, need to be capable of managing clients who have multiple drug dependencies and co-existing anxiety and depressive disorders.