A study released today in PLoS Medicine compares alcohol, tobacco, and illegal drug use across seventeen different countries participating in the World Health Organization World Mental Health Survey Initiative.Alcohol seems to be widely used in the studied countries, tobacco less so but fairly evenly used. Major variation was found with marijuana and cocaine use, with the US and New Zealand at the top of the list for pot, and the US as a significant outlier with cocaine use, to the extent that if cocaine was not used in the US, it seems unlikely that it would even be a major part of a study such as this one.How the study was done:
Eighteen surveys were carried out in 17 countries in theAmericas (Colombia, Mexico, US), Europe (Belgium, France,Germany, Italy, Netherlands, Spain, Ukraine), the Middle Eastand Africa (Israel, Lebanon, Nigeria, South Africa), Asia(Japan, and separate surveys in Beijing and Shanghai in thePeople’s Republic of China), and Oceania (New Zealand). Thisset of countries was determined by availability of collaboratorsin the country who were able to obtain funding for thesurvey and complete the World Mental Health Surveys(WMHS) protocol.
The sample sizes are in the thousands, with a total sample of 85,052 individuals.The results:This study looked at a lot of different aspects of substance use (see conclusions, below) but the most interesting results are summarized in the following table. (See the original paper for a more detailed breakdown.) This is based on the study’s Table 2 and presents the percentage of use by respondents in each country of alcohol, tobacco, cannabis (marijuana) and cocaine.The study concluded:
- Drug use is unevenly distributed across countries.
- The US had among the highest use rates of all drugs.
- Lower levels of drug use are seen in poorer countries, espeically in Africa and the Middle East.
- Greater drug use is seen in younger than older adults globallly, suggesting change in drug use over historic time.
- There is more drug use among males than among females, but this gender gap seems to be closing.
- The period in their lives during which people used illegal drugs is lenthening, into older ages.
- Generally speaking, the higher the income, unmarried status, amd male-ness are linked to a higher chance of illegal drug use within countries, and generally, more affluent countries are associated with more drug use.
The study does have a number of limitations that re clearly reported. For example, the poorest of countries are not represented because resources from the countries in which the study was carried out were required. Also, there was a great deal of variation in response and participation for other reasons.Questions that I have about this study include:The African and Middle Eastern countries where drug use rate is lower may also be more Islamic. Does this have an effect? Christianity seems more widespread in the countries with more drug use. Is this relevant? Does the observed age difference (younger cohorts with more drug use) reflect a reporting bias or a reality? It seems that over the last several decades the evidence that younger people are using more drugs is so often reported that all people must be using all drugs by now, but they aren’t! Do studies that show declines in drug use get less press, or go unfinished? (Is there a reporting bias or a confirmation bias at work here?)
Degenhardt L, Chiu W-T, Sampson N, Kessler RC, Anthony JC, et al. (2008) Toward a global view of alcohol, tobacco, cannabis, and cocaine use: Findings from the WHO World Mental Health Surveys. PLoS Med 5(7): e141. doi:10.1371/journal. pmed.0050141 Received: June 26, 2007
The original paper is HERE.