The ultimate challenge in Psychiatry today is the treatment of patients suffering simultaneously from both psychotic disorders and substance abuse. Cannabis is the most widely used illicit substance in the Western world. Scientists believe that cannabis is related to psychosis as it interrupts the operation of neurotransmitters like dopamine and this disrupts the organism's normal function.

This research focuses on 14 cases of young patients treated in a private psychiatric clinic, who developed psychotic symptoms after cannabis abuse without having any prior psychiatric problems. For the conduct of this study we took under consideration:

The age when the abuse started

The abuse frequency

The abuse time period

Family history of psychiatric disorders or substance abuse

The onset of psychotic symptoms

A combination of psychotherapy and pharmacologic therapy was used in the treatment of those patients. Their average hospitalisation time was 1.67 months.

Cannabis abuse seems to have caused patients psychotic symptoms while they did not have any active psychiatric disorder prior to the abuse. The abuse interruption along with suitable drug treatment contributed to the control of the psychotic symptoms. A 3 year follow-up revealed that 8 out of 14 patients re-abused cannabis, 4 had psychotic symptoms without cannabis abuse, while only 2 recovered fully from both.

The patient history study generates the question whether cannabis abuse is the cause of psychosis or merely a consequence. Cannabis abuse can be a causal factor however it is not a necessary and adequate prerequisite for psychosis.