Challenges of marijuana research.

The use of any drug ideally represents a decision based on objective, scientifically based cost–benefit analyses that factor in both the short and long-term effects of that exposure. Pharmacological, toxicological, pharmacokinetic and phar-macodynamic investigations that are deemed to be essential for the rational use of any therapeutic agent are therefore part of the usual drug approval process. With regard to marijuana, sociopolitical factors have intervened in this scientific process. Three major lay perspectives appear to dominate the societal view of marijuana—the 'reefer madness' camp holding the view that there are no redeeming attributes to the 'evil weed', the 'innocuous' camp who consider it to be a harmless recreational substance and the 'medical marijuana' camp that believes marijuana to be a panacea for a multitude of aches, pains and chronic diseases with, of course, every shade of opinion in-between. On the scientific front, three trends preface nearly every recent journal article concerning marijuana—the significant prevalence of marijuana use, the changes in age of first use (Kohn et al., 2005; Monshouwer et al., 2005) and the increasing strength of the drug, leading to higher acute and chronic exposures Americans aged 12 and older were considered to have used marijuana within their lifetime, the last year, and the last month, respectively (Office of National Drug Control Policy, 2006). However, in the 3 of the 11 states in which medical use of marijuana is legal, and for which statistics are available, 0.05% of the population are registered, i.e. legal, users (General Accounting Office, 2002). Even though marijuana is available from pharmacies in the Netherlands, 80% of users secure their drug via illicit channels (Erkens et al., 2005). Therefore, large numbers of people—adults, pregnant women, adolescents and children—acutely and/or chronically inhale/ingest imprecise dosages of marijuana of unknown purity via pharmaceutically inelegant dosage forms without the complement of knowledge concerning the pharmacological actions, the toxicological risks and the pharmaceutical quality of the product that would be required for the approval and use of any other drug. Cogent, scientifically based research into marijuana is essential but is also very difficult for a number of important reasons. Firstly, there are logistical issues inherent in studying any substance that is illegal in most countries. Specifically, there are numerous hurdles that must be surmounted to secure a Schedule I substance approval for acute studies; there are problems with subject memory and honesty in determining recent and chronic exposures; and there …