Sequence of onset of different drug use among opiate addicts

The temporal sequence of drug use should reveal which drugs are precursors to heroin and which drugs are used subsequent to the establishment of heroin addiction as adjunctive drugs. This temporal sequence was examined in an epidemiological study. Out of 249 opiate addicts interviewed in the area of Penang, Malaysia, this sequence of drugs could be obtained in 248 cases. The mean (median) age for first use of nicotine is 15.5 (15) years, alcohol 18.4 (18) years, cannabis 17.8 (17) years, heroin 21.8 (21) years, opium 22.8 (22) years, and benzodiazepines 25.8 (25) years. The age of first use of different drug types is presented in some detail. The patterns of sequence of drug use was analyzed for the five major and most frequently reported drugs, i.e. alcohol, cannabis, heroin, opium and benzodiazepines. Nicotine, used as first drug in almost all cases, was omitted in this analysis. A clear trend to multiple drug abuse emerges from this analysis; the biggest number of cases were users of 4 drugs (81 cases), followed by 3 drugs (59 cases) and 5 drugs (58 cases). Thus, nicotine, alcohol and cannabis are precursors of heroin addiction. Other adjunctive drugs become important only after heroin addiction. Among these substances, opium and benzodiazepines are numerically preponderant.