Cannabis: some psychiatric aspects

Cannabis use is widespread and, amongst the drugs of abuse, it is one of the commonest. It ran induce psychotic symptoms and regular use is associated with both 'organic' and 'functional' syndromes of acute psychosis. There is insufficient support for the existence of a chronic form of psychosis associated with cannabis use or the entity of 'amotivational syndrome'. Psychotic symptoms are worsened by cannabis abuse in patents diagnosed with schizophrenia and this has implications in clinical practice. Preliminary evidence indicates that prolonged use may enhance individuals' vulnerability to developing schizophrenia. The discovery of cannabis receptors and the endocannabinoid systems may increase our understanding of the biological mechanisms of psychosis in the future.