The challenges of 'medical cannabis' and mental health: a clinical perspective.

The use of cannabis as a medicine has a long tradition in Western medicine. It has been seen as a viable option for the treatment of various neurological and psychiatric conditions, and recently there is again interest in the place of cannabinoids in the pharmacopoeia. What has become increasingly clear, however, is these benefits need to be weighed carefully against the potential difficulty associated with herbal cannabis and cannabinoid compounds for an individual's mental health. This challenges the use of cannabis as a medication and the regulation of its prescription.