NEW YORK (Reuters Health)—A new study shows a connection between adolescent marijuana use and psychosis, but also indicates that the reverse could hold true; adolescents with psychosis may turn to marijuana to ease symptoms.
“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.
The study, published recently in the journal Addiction, followed-up from an earlier study in 2010. Then, researchers studied 3,800 Australian teenagers and concluded that those who used marijuana were twice as likely to develop psychosis versus teens who never smoked pot.
For the new study, researchers examined if teens who suffered from hallucinations and delusions were likely to use pot earlier than most teens and adults. Scientists used information from 2,120 Dutch teenagers who had admitted to pot use and who were given psychosis vulnerability tests.
Although researchers say that the study can’t prove one causes the other, they said a bi-directional relationship exists.
“What is interesting in this study is that both processes are going on at the same time,” said Dr. Gregory Seeger, medical director for addiction services at Rochester General Hospital in upstate New York, told Reuters.
“I think the marijuana is not a harmless substance. Especially for teenagers, there should be more of a public health message out there that marijuana has a public health risk,” Dr. Marta Di Forti told Reuters.
In early December, an annual Monitoring the Future survey was released that concluded marijuana use is holding steady among U.S. teens, particularly among eighth, 10th- and 12th-graders.
This year, 6.5% of 12th-graders said they smoke marijuana daily. That’s slightly down from 2011, when 6.6% said they smoked it daily.
Teens’ perception about the harmfulness of using marijuana was down, which may signal future increases in marijuana use, according to the study’s principal investigator, Lloyd Johnston.
Overall, 41.7% of eighth-graders perceive occasional marijuana use as harmful and 66.9% see regular use as harmful. As teens get older, their perception of harm decreases, the survey showed, with only 20.6% of 12th-graders seeing regular use as harmful.
To read more on the study, click here.
***information from CNN contributed to this report.