University of Otago researchers have put together a very good website on the cannabis referendum. It doesn’t tell you how to vote but presents data from the gold class Dunedin and Christchurch longitudinal studies.
Some of their findings:
- 80% of adults have tried cannabis at least once
- When they were young adults, around 50% had used in the last year
- Cannabis use starts to decline in early 30s
- Around 4% to 10% of population are diagnosed as cannabis dependent
- There is a relationship between cannabis use and other drug use, with it being strong if people start regular cannabis before age 17
- Cannabis use elevates the chance of psychotic symptoms, but the size of the risk relation is small
- A loss of 8 IQ points was found amongst study members who began using cannabis in adolescence and continued until age 38
- Overall the major risk is with those who begin using in adolescence or are dependent
- The illegal status of cannabis does not prevent some people from using
- Arrests and convictions do not lead to a reduction in use
To me this reinforces that a health based approach is the best way to reduce harm from cannabis use.