Cannabis: some psychiatric aspects

Cannabis use is widespread and, amongst the drugs of abuse, it is one of th e commonest. It ran induce psychotic symptoms and regular use is associated with both 'organic' and 'functional' syndromes of acute psychosis. There i s insufficient support for the existence of a chronic form of psychosis ass ociated with cannabis use or the entity of 'amotivational syndrome'. Psycho tic symptoms are worsened by cannabis abuse in patents diagnosed with schiz ophrenia and this has implications in clinical practice. Preliminary eviden ce indicates that prolonged use may enhance individuals' vulnerability to d eveloping schizophrenia. The discovery of cannabis receptors and the endoca nnabinoid systems may increase our understanding of the biological mechanis ms of psychosis in the future.