WASHINGTON (CBS DC) — Marijuana use is being linked in both cause-and-effect directions between teens and symptoms of psychosis.
Researchers at Leiden University in the Netherlands believe that marijuana use may be linked to the development of psychotic symptoms in young people.
But they also believe that psychotic symptoms in teens may lead them to use pot.
“We have focused mainly on temporal order; is it the chicken or the egg? As the study shows, it is a bidirectional relationship,” wrote the study’s lead author Merel Griffith-Lendering, a doctoral candidate at Leiden University in The Netherlands, in an email to Reuters Health.
Previous research on the topic has established links between the two, but no conclusive evidence has been found to pointing to any exact causality.
A 2010 study of 3,800 Australian teenagers found that those who used marijuana were twice as likely to develop psychosis compared to teens who never smoked pot.
The U.S. National Library of Medicine defines “psychosis” as a loss of contact with reality that usually includes false beliefs about what is taking place or one who is experiencing delusions among the five senses – such as seeing or hearing things that are not present in reality.
Griffith-Lendering and her colleagues used information on 2,120 Dutch teenagers who were surveyed about their use of marijuana when they were about 14, 16 and then 19 years old.
The teens also took psychosis vulnerability tests that asked – among other things – about their ability to concentrate, their feelings of loneliness and whether they see things other people don’t.
Overall, the researchers found that 940 teens, or about 44 percent, reported smoking pot, and there was a bidirectional link between pot use and psychosis.
These studies come at a time when marijuana has become a hot political debate in America, and has been fully legalized in both Colorado and Washington state.
A recent Pew Research poll found that young Americans under the age of 30 favor legalizing the use of marijuana by a 54 percent-42 percent margin. Opinion is divided among those in middle age groups. Those 65 and older are broadly opposed to legalization (66 percent illegal, 30 percent legal).
Griffith-Lendering and her colleagues conceded that proving one causes the other is a difficult task – especially when factoring in genetics.