Gene explains cannabis psychosis link
A genetic variation uncovered by MRC investigators helps explain why cannabis triggers psychosis in some young users but not others. In a study of 1,000 people followed from birth to 32 years, those who possessed a common variation in the COMT gene and used cannabis frequently in their adolescence had a five-times higher risk of developing psychosis than individuals without the gene who used cannabis. Furthermore, around 15 per cent of participants in the former group went on to develop schizophrenia.
Biological Psychiatry 2005; 57: 1117-1127