Prevalence and age of onset for drug use in seven international sites: results from the international consortium of psychiatric epidemiology

Abstract

This study compares lifetime prevalence and age of first use (onset) for alcohol, cannabis, and other drugs in six international sites. Data from seven epidemiologic field surveys that used compatible instruments and study designs were compiled for cross-site analyses by the International Consortium of Psychiatric Epidemiology (ICPE). The world health organization's composite international diagnostic instrument (WHO-CIDI) and additional items were used to ascertain drug use in each site. Lifetime use rates were estimated for alcohol, cannabis, and other illicit drugs. Survival analyses were used to estimate age of onset. Study settings and main results: use of alcohol twelve or more times ranged in descending order from the Netherlands (86.3%), United States (71.7%), Ontario, Canada (71.6%); São Paulo, Brazil (66.1%), Munich, Germany (64.9%), Fresno, California (USA) (51.9%), to Mexico City (43.2%). Use of cannabis five or more times in a lifetime ranged from 28.8 in the United States to 1.7% in Mexico City, and other drugs ranged from United States (19.4%) to Mexico City (1.7%). Age of first use was similar across study sites. This study demonstrates the fundamental uniformity of onset patterns by age as contrasted with wide variations in lifetime prevalences across sites. Study findings suggest that drug use patterns may change among emigrating populations from low consumption nations as a consequence of international resettlement in nations with higher rates. Methodological limitations of the study along with recommendations for future international comparative research are discussed.

Drug use and dependence in cocaine dependent subjects, community-based individuals, and their siblings

“…In addition, cocaine was the most "addictive" drug of all the substances used by the community-based comparison population, meaning that among those who have used any substance, the percentage of that group who progress to dependence was the highest. Conditional dependence for cocaine in this population was over 50% which is higher than generally recognized population rates (Vega et al, 2002;Warner et al, 1995). Similarly, in the sibling groups, cocaine was the most addictive for men and women.…”

“…Kendler et al reported a 16%-18% prevalence of lifetime cocaine use whereas 34% of our community based subjects reported cocaine use (Kendler et al, 2003;Kendler and Prescott, 1998). There were also greatly increased rates of dependence in the community sample compared to other population based studies (Vega et al, 2002;Warner et al, 1995). Because our communitybased subjects were matched by zip code, this suggests that socioeconomic or "neighborhood" factors contributed to these elevated rates of drug use and dependence.…”

Early Onset Cannabis Use and Progression to other Drug Use in a Sample of Dutch Twins

“…Specifically, despite the liberal approach to cannabis use in the Netherlands, rates of cannabis use are substantially lower in that country than in Australia, the US and many other countries. For example, a recent study comparing rates of drug use in seven countries (Vega et al, 2002) noted that the lifetime rate of cannabis use in the Netherlands (12.3%) was less than half of that in the US (28.8%) while a comparable estimate for Australia is that 39.3% of the adult population have used cannabis (Australian Institute of Health and Welfare, 1999). Thus, cannabis use may represent a norm-violating and unconventional behavior in the Netherlands in much the same way as it does in Australia and other countries that adopt more punitive legal approached to cannabis.…”

Clinical and research utility of Spanish Teen-Addiction Severity Index (T-ASI)

“…Recent epidemiological studies in different countries have raised concerns regarding an increased risk of psychoactive drug use among adolescents (Vega et al, 2002). This trend towards "normalization" in the use of drugs such as cannabis and cocaine among young people could be especially dangerous for those adolescents with co-morbid psychiatric disorders (Armstrong & Costello, 2002).…”