Many studies have identified an association between marijuana use and an increased risk of developing mental illness, a previous study showed that individuals who smoked pot developed psychotic disorders nearly 3 years earlier than people who didn't use the drug.
Scant research has explored whether or not it could be the other way round. This new Dutch study, published in the journal Addiction, is one of the first of its kind to look into whether teenagers with mental illness may be more inclined to use marijuana to relieve some of their symptoms - what some refer to as "self-medicating with marijuana".
The big question is whether marijuana use causes psychosis or if teenagers with psychotic symptoms are more inclined to use the drug.
Lead author of the study Merel Griffith-Lendering, a doctoral candidate at Leiden University in The Netherlands, said: "We have focused mainly on temporal order; is it the chicken or the egg? As the study shows, it is a bidirectional relationship,"
Dr. Gregory Seeger, medical director for addiction services at Rochester General Hospital in upstate New York, said: "What is interesting in this study is that both processes are going on at the same time,"
He noted how a teenage brain is still very vulnerable as it is still developing. The effects of the main active compound in pot called tetrahydrocannabinol (THC) has been found to even potentially reduce the IQ of teenagers who take the drug.. Not only this, but people with a family history of mental illness are more sensitive to the toxic effects of THC.
A previous study conducted in Australia involving over 3,800 adolescents found that those who smoked marijuana were twice as likely to develop psychotic symptoms than those who didn't. However results from the same study indicated that those who suffered from hallucinations or delusions were also found to more likely start smoking pot at a younger age.
Over 2,120 Dutch teenagers were questioned about how often they smoked marijuana at ages 14, 16 and 19. They were also asked whether they see things that others do not, how well they are able to concentrate, and if they ever experience feelings of loneliness.
Around 44 percent of the teens surveyed admitted to smoking pot, the researchers also identified a bidirectional link between cases of psychosis and pot use. Smoking pot was linked to the development of psychotic symptoms after three years while at the same time they found that cases of psychosis led to marijuana consumption after three years. They also factored in alcohol and tobacco use, as well as family history of mental illness.
The researchers couldn't determine whether marijuana use directly increases the risk of developing psychotic symptoms.
According to Dr. Marta Di Forti, of King's College, London:
"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."
It is important that people understand that there may be risks associated with marijuana use that aren't completely understood yet.
Written by Joseph Nordqvist