MARIJUANA SMOKING TEENS PRONE TO SCHIZOPHRENIA

Teens who smoke marijuana are at a greater risk of developing
schizophrenia and psychotic symptoms in the future, a new study has
found.

After observing more than 3800 youngsters, researchers learnt that
people who used the drug for six or more years were twice as likely to
suffer from delusional disorders than those who never used it.

Researchers from Queensland Brain Institute, at the University of
Queensland, quizzed 3801 young adults who were born in Brisbane
between 1981 and 1984.

Among the 1272 participants who had never used marijuana, 26 (2 per
cent) were diagnosed with psychosis, while the 322 people who had used
marijuana for six or more years, 12 (3.7 per cent) were diagnosed with
the illness.

The average age of the participants was about 20.

According to the authors, the study was the first to look at sibling
pairs to discount genetic or environmental influence.

"This is the most convincing evidence yet that the earlier you use
cannabis, the more likely you are to have symptoms of a psychotic
illness," the Sydney Morning Herald quoted Dr McGrath, a professor at
the institute, as saying in a statement.

McGrath added: "The message for teenagers is: if they choose to use
cannabis they have to understand there's a risk involved."

The study noted: "Apart from the implications for policy makers and
health planners, we hope our findings will encourage further clinical
and animal-model research to unravel the mechanisms linking cannabis
use and psychosis."

The research has been published online by the Archives of General
Psychiatry