Substance use patterns associated with injection drug use initiation in a low-threshold methadone-maintained sample

Substance use patterns associated with the initiation of injection drug use were examined in a sample of low-threshold methadone-maintained injection drug users. Injection initiation tended to coincide with concurrent heavy alcohol and cannabis use, increasing use of stimulants such as cocaine, and the onset of prescription opioid and sedative misuse. Nearly half of the sample reported simultaneously using at least one other drug (excluding tobacco) during the first-ever injection drug use session, with alcohol being the most commonly co-administered substance. Findings suggest that specific patterns of multiple substance use may be appropriate targets for prevention of injection drug use.