Marijuana use of teens and psychosis are linked bidirectional

Marijuana use of teens was statistically linked to psychosis, while also finding teens with preexisting psychotic issues to be more likely to consume pot in later years, according to a new study from researchers in the Netherlands. The study is based on answers from 2,120 Dutch teenagers and tried to discover if pot use could lead to psychosis or visa versa.

The researchers first questioned the teens on their pot use habits between the ages of 14 and 19, then testing them for potential psychosis. They found that there was, in fact, a relationship between both using marijuana and developing psychosis and those who develop psychosis experimenting with pot.

"We have focused mainly on temporal order; is it the chicken or the egg? As the study shows, it is a bidirectional relationship," said the study's lead author Merel Griffith-Lendering. For example, using pot at 16 years old was linked to psychotic symptoms three years later, and psychotic symptoms at age 16 were linked to pot use at age 19.

Peer reviewer Dr. Marta Di Forti, of King's College, London confirmed the news saying: "We can say for some people that cannabis comes first and psychosis comes second, but for some people they have some (undiagnosed) psychosis (and) perhaps cannabis makes them feel better."

The new study thus comes to the same conclusions as an earlier study from 2010 of 3,800 Australian teenagers, which also found a bidirectional link. Cannabis could thus be labeled as a risk factor, but not a cause for psychotic disorders.