Magazine article Clinical Psychiatry News

Opioid Dependence Likely Plays Role in Drug Co-Use Patterns

Magazine article Clinical Psychiatry News

Opioid Dependence Likely Plays Role in Drug Co-Use Patterns

Article excerpt

Sequential co-use of heroin and cocaine was more common than both heroin use alone and simultaneous use of the two drugs, and less common than cocaine use alone in a cohort of intravenous drug users in Montreal not receiving methadone treatment for heroin addiction.

Neither the use of cocaine nor heroin appeared to increase or decrease the use of the other, according to Francesco Leri, Ph.D., of the University of Guelph (Ont.) and colleagues.

These findings differ from those of previous studies of co-use habits among methadone-dependent populations, which have shown that opioid addicts who use both heroin and cocaine use significantly more cocaine than those who do not use heroin, and those who use cocaine administer heroin more frequently than those who use heroin only. The contrast supports the idea that a history of opioid dependence plays a role in the interaction between heroin and cocaine intake, they said (Rev. Psychiatr. Neurosci. 29[1]:40-47, 2004).

Of 1,111 non-methadone-treated individuals selected from a cohort of injection drug users in Montreal, 353 reported no heroin and no cocaine (NHC) use in the month prior to the study interview; 568 reported having used cocaine only (C); 55 reported having used heroin only (H); and 135 reported having used both intravenous heroin and intravenous cocaine (HC).

Statistical analysis of the reported data showed that among injectors of either heroin only or cocaine only, heroin was used on a significantly greater number of days than cocaine, and heroin use tended to be fairly regular, with 47% of users injecting between 20 and 30 days per month. In contrast, cocaine use was more sporadic, with 57% of the cocaine-only group using between 1 and 10 days per month.

Although cocaine use was more sporadic in terms of number of days used, "when it was used, it was injected significantly more often than heroin," Dr. Leri and associates said. In the cocaine-only group, 52% injected between three and eight times daily. In the heroin-only group, 66% injected between one and two times daily--a statistically significant difference in distribution.

The investigators also compared intravenous heroin and intravenous cocaine use in single-drug vs. …

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