• Cannabis;
  • marijuana;
  • poverty;
  • prohibition;
  • welfare

The moral status of cannabis was transformed from medicine to vice in the early 20th century by claims about its malevolent consequences. In the United States, for example, a 1934 Bureau of Narcotics report claimed that ‘fifty percent of the violent crimes committed by Mexicans, Turks, Filipinos, Greeks, Spaniards, Latin Americans and Negroes may be traced to the abuse of marihuana’. It quoted a narcotics officer: ‘Marihuana has a worse effect than heroin. It gives men the lust to kill, unreasonably, without motive—for the sheer sake of murder itself’[1]. In the 1936 film Reefer Madness, a few puffs caused sexual assault and homicide. In 1937, Congress criminalized cannabis.

Thirty years later, as cannabis use became widespread among normal, middle-class citizens, claims that it caused violence and crime lost credibility. Prohibitionists then shifted their arguments, claiming cannabis was dangerous because it had the opposite effect, draining users of all motivation [2]. More recently, new claims have been made of a link between cannabis and psychosis [3].

Pedersen's study of Norwegian young people [4] suggests that cannabis use is associated with poverty, too, or at least with receipt of welfare, which implies documented need. His prospective, longitudinal data, careful testing of several possible confounders, and finding of a dose-related relationship all give confidence in his correlation. He is admirably cautious in his interpretations and candid about the limitations of his study. None the less, there are a few issues regarding specification of variables that might be considered in future research.

The core independent variable, cannabis use, is measured in ranges, with the link to welfare holding only for those who used cannabis 50 times or more; but in a population sample such as this, there are probably people who have used many hundreds of times. A continuous variable could show whether the observed association with welfare was created by a small number of extreme users within the 50+ group.

The core dependent variable is a dummy variable, received welfare or not, which tells us nothing about the reasons for assistance (disability, ill health, prolonged unemployment). Apart from this, we do not know what, if anything, receipt of welfare means or what its link to cannabis might be. Is cannabis thought to cause poverty or disability and thus the need for assistance? To his credit, Pedersen notes that he is ‘not able to explain the mechanisms behind these associations . . .’. More detailed measures of need could help. In his data set, socio-economic status is measured indirectly by parental occupation and education. Direct measures of respondents' income could tell us more about need and its possible links to cannabis use.

Pedersen's study is generally well conducted, but the silent paradigm around such studies is troubling. Why are questions of this genre so often asked, funded and published? A proper answer would show the political uses of drug problems and how the drug control industry holds in place a fear-based frame around drug use. Here I can only suggest that studies searching for associations between cannabis and a long line of unwanted behaviors constitute ‘normal science’[5] within what I call the ‘malevolence paradigm’. Research within this paradigm presumes that cannabis causes trouble and then hunts for it.

Pedersen states that his study ‘adds to the existing evidence of the possibly harmful social consequences of cannabis use’. His core finding of an association between cannabis and welfare is based on the 46 respondents (of 2606) who used cannabis more than 50 times. Prevalence of cannabis use is low in Norway, but in nearly all other modern societies cannabis is used routinely by millions of accomplished, socially integrated people [6]. This raises a fundamental question of theoretical logic: if some small sliver of cannabis users are more prone to receive welfare assistance (or engage in crime, or report ‘psychotic symptoms’, etc.), should scientists look to the drug—consumed unproblematically by the vast majority of users—or should they look at the characteristics of problematic users and their milieu?

The malevolence paradigm precludes important questions from being asked. To understand the relationship between cannabis and welfare it would be useful to know how many people get by without welfare because they earn income from small-time cannabis growing? Drug journals have published more than 200 papers on possible links between cannabis and mental illness, but on the rare occasions when cannabis users are asked what advantages they derive from cannabis, the most common themes are relaxation, anxiety relief and stress reduction [7]. The question of whether cannabis ever confers mental health benefits or reduces the need for mental health services remains uninvestigated.

Even thoughtful studies such as Pedersen's tend to feed the criminalization narrative: because cannabis appears associated with unwanted behaviors—no matter how rare, or how partial and contingent the association—continued prohibition is warranted. This non-sequitur is smuggled into public discourse, shapes public policy and reaffirms the malevolence paradigm.


  1. Top of page
  2. Declaration of interests
  3. References
  • 1
    Bonnie R. J., Whitebread C. H. The Marijuana Conviction: A History of Marijuana Prohibition in the United States. Charlottesville, VA: University Press of Virginia; 1974, p. 1467.
  • 2
    Himmelstein J. The Strange Career of Marijuana. Westport, CT: Greenwood Press, 1983.
  • 3
    McLaren J. A., Silins E., Hutchinson D., Mattick R. P., Hall W. Assessing evidence for a causal link between cannabis and psychosis. Int J Drug Policy 2010; 21: 1019.
  • 4
    Pedersen W. Cannabis and social welfare assistance: a longitudinal study. Addiction 2011; 106: 163643.
  • 5
    Kuhn T. The Structure of Scientific Revolutions. Chicago, IL: University of Chicago Press; 1962.
  • 6
    Eisenbach-Stangel I., Moscalewicz, J., Thom, B., editors. Two Worlds of Drug Consumption in Late Modern Societies. Surrey, UK: Ashgate; 2007.
  • 7
    Reinarman C., Cohen P. Law, culture, and cannabis: comparing use patterns in Amsterdam and San Francisco. In: EarleywineM., editor. Pot Politics. New York: Oxford University Press; 2007, p. 113137.