Cannabis use increases the risk of developing schizophrenia and psychotic patients should definitely not be encouraged to smoke it to relieve symptoms, research on the subject in Malta confirms.

Studies have shown the strong association between cannabis use and psychosis and the local research, recently published in an international scientific journal, supports that link. It also shows that the more cannabis is used, the worse the prognosis.

The first epidemiological study on psychosis in Malta also shows that the age of onset of psychosis is significantly younger in those using cannabis.

“We can tell schizophrenia patients, who smoke cannabis to relieve negative symptoms, that their outcome will simply be worse. And we are backed scientifically to say this,” said Anton Grech, who led the study, together with Rachel Taylor-East and Nigel Camilleri.

The presentation on Cannabis, Psychosis And the Malta Connection was made at the start of a two-day seminar on Addictions at the Dolmen Resort Hotel in Qawra yesterday. It is organised by the Maltese Association of Psychiatric Nurses, in collaboration with the Malta Association of Psychiatric Trainees.

The data, collated about three years ago, shows that certain areas – the inner harbour region and Gozo – have a higher incidence of schizophrenia than others. The increased rate of psychosis was identified in the lowest socio-economic and the most densely populated region in Malta.

It showed that areas of social deprivation were a risk factor, although Gozo was puzzling because research showed schizophrenia was usually lower in rural areas, Dr Grech said.

He explained it was probably due to genetic factors but also because of heightened stigma and, therefore, a longer time taken before going to hospital.

One of the most striking findings was the immensely high psychosis in illegal immigrants, he said. It was 10 times the incidence among the Maltese population.