*The following is excerpted from an online article posted on Medical News Today.
Studies have long suggested a link between marijuana use and psychosis. New research sheds further light on this association, after finding that teenagers who increase their use of the drug are more likely to experience psychotic-like episodes.
The study also reveals that the link between frequent marijuana use in adolescence and the risk of psychotic symptoms may be largely mediated by symptoms of depression.
Lead study author Josiane Bourque, of the Department of Psychiatry at the University of Montreal in Canada, and colleagues published their findings in the Journal of Child Psychology and Psychiatry.
According to the 2015 National Survey on Drug Use and Health, marijuana remains the "most commonly used illicit drug" in the United States, with more than 22.2 million past-month users.
In recent years, legalization of marijuana for recreational purposes, medicinal purposes, or both, has risen in the U.S. Studies have indicated that this rise in legalization has reduced perceptions of marijuana as a harmful drug, leading to an increase in its use, particularly among teenagers.
In 2016, around 5.4 percent of 8th graders, 14 percent of 10th graders, and 22.5 percent of 12th graders reported having used marijuana in the past month.
Previous research has linked marijuana use with symptoms of psychosis, such as hallucinations, delusions, and changes in mood and behavior.
For this latest study, Bourque and team sought to determine how marijuana use in adolescence might influence the risk of psychotic-like experiences (PLEs).
"To clearly understand the impact of these results, it is essential to first define what psychotic-like experiences are: namely, experiences of perceptual aberration, ideas with unusual content and feelings of persecution," notes Bourque.
The research included the data of 2,566 teenagers from Canada, all of whom were aged between 13 and 16 years. Every year for a total of 4 years, the teenagers completed questionnaires that assessed their drug use and the occurrence of any psychiatric symptoms.
Additionally, the adolescents underwent a series of cognitive tests that assessed their IQ, long-term memory, working memory, and inhibitory control skills.
Compared with teenagers in the general population, the researchers found that teenagers who increased their frequency of marijuana use from occasionally to weekly or daily were at 159 percent greater risk of having recurrent PLEs.
Source: Medical News Today