Science Cannabis

The Recreational Use of Cannabis 223Table 6.3. Adverse Effects Attributed to Cannabis by 2794 British UsersEffect% ReportingImpaired memoryParanoiaAmotivation/lazinessRespiratoryAnxiety/panicCognitive impairmentNauseaDependencePsychosisTotal Reporting Problems6.15.64.84.21.81.71.30.60.421.0The Potency of Illicit MarijuanaOne of the claims frequently made by opponents of the recreational useof marijuana is that the cannabis used today is far more potent than therelatively harmless low-THC herbal material smoked by the flower powergeneration of the 1960s and 1970s. It is claimed that the supplies ofcannabis available today are 10, 20, or even 40 times more potent thanpreviously. As Professor Heather Ashton put it in her evidence to theHouse of Lords (1998) enquiry:The increase in potency is important because the physical and psychologicaleffects of cannabinoids (THC and others) are dose-related: the biggerthe dose the greater the effect. Most of the research on cannabis was carriedout in the 1970s using relatively small doses, and much of that researchis obsolete today. The acute and long term effects of the presenthigh dose use of cannabis have not been systematically studied.But is it really true that the commonly available cannabis today ismore potent? And does it matter? For more than 20 years the UnitedStates government has sponsored the Potency Monitoring Project at theUniversity of Mississippi that has been measuring the THC content ofseized samples submitted by law enforcement agencies throughout theUnited States. At the meeting of the International Cannabinoid Research