Applicable in: England and Scotland

The first major study of long-term cannabis users in the UK found that cannabis was not an important predictor of differences in the perceived effects of cannabis on aspects of health nor in relation to reported health problems (Coggans et al. 2002). The study used a sample of 405 participants who had used cannabis weekly for at least ten years with a period or periods of abstinence of no more than 12 months during that time (Mean age was 33). The study was unable to determine whether the sample was representative of the wider population of long-term smokers in the UK. While the impact of cannabis on health was accessed using the General Health Questionnaire and self-reports of health problems related to cannabis use, the absence of clinical examination may have meant that the impact of cannabis smoking on lung function in this group was missed.

References
Coggans, N., Dalgarno, P., Johnson, L. and Shewan, D. (2002). Long-term heavy cannabis use. Research report submitted to the Department of Health. University of Strathclyde.