Home Affairs Committee - Drugs: Breaking the CycleWritten evidence submitted by John Cavendish (DP039)

I am someone who suffers from schizophrenia and find that cannabis use is a great help in giving relief from the side effects of anti-psychotic medication. I have a brother who also has schizophrenia but he never used cannabis. Cannabis does not cause schizophrenia as proven recently.1

A recent systematic review concluded that cannabis use increases risk of psychotic outcomes independently of confounding and transient intoxication effects. Furthermore, a model of the association between cannabis use and schizophrenia indicated that the incidence and prevalence of schizophrenia would increase from 1990 onwards.

The model is based on three factors:

(a)increased relative risk of psychotic outcomes for frequent cannabis users compared to those who have never used cannabis between 1.8 and 3.1;

(b)a substantial rise in UK cannabis use from the mid-1970s and;

(c)elevated risk of 20 years from first use of cannabis.

This paper investigates whether this has occurred in the UK by examining trends in the annual prevalence and incidence of schizophrenia and psychoses, as measured by diagnosed cases from 1996 to 2005. Retrospective analysis of the General Practice Research Database (GPRD) was conducted for 183 practices in England, Wales, Scotland and Northern Ireland. The study cohort comprised almost 600,000 patients each year, representing approximately 2.3% of the UK population aged 16 to 44.

Between 1996 and 2005 the incidence and prevalence of schizophrenia and psychoses were either stable or declining. Explanations other than a genuine stability or decline were considered, but appeared less plausible. In conclusion, this study did not find any evidence of increasing schizophrenia or psychoses in the general population from 1996 to 2005.

I do not believe that it is acceptable for politicians to have laws making it illegal to get intoxicated or just possess a drug for recreational use, I urge the committee to review the Drugs policy of Portugal and bring in similar laws to the UK.

Regulation of intoxicants would be far safer for the public than allowing a hard crime element to run the show.

January 2012

1 www.schres-journal.com/article/PIIS0920996409002692/abstract?rss=yes

Prepared 8th December 2012