[Cannabis and psychosis].

Cannabis is abused by a progressively larger and younger proportion of our population. For the clinician, this can raise the question of what the relationship between cannabis and psychosis is. For the patient who is already psychotic, this relationship is most certainly adverse; cannabis worsens the symptoms and prognosis of a psychosis. What may be of even greater concern is the growing evidence that cannabis may cause psychosis in healthy individuals. Many studies now show a robust and consistent association between cannabis consumption and the ulterior development of psychosis. Furthermore, our better understanding of cannabis biology allows the proposal of a plausible hypothetical model, based notably on possible interactions between cannabis and dopaminergic neurotransmission.