New study: Smoking weed as a teen causes “increased risk of psychosis”

“(It) showed that use can impact inhibitory control, working memory, delayed memory recall, and perceptual reasoning.”
Marijuana in jars from TMW

It may be common knowledge that using drugs and alcohol as a teen isn’t good for you, but now we have a study that shows just how bad it really is.

The American Journal of Psychiatry has released a new study where they followed 4,000 students over a timespan of four years and tracked their cannabis use.

“(It) showed that use can impact inhibitory control, working memory, delayed memory recall, and perceptual reasoning.”

A few quick takeaways from the study are:

  • Effects of cannabis are considerably greater than those of alcohol.
  • Concurrent and lagged cannabis use have effects on several cognitive functions.
  • Tenth graders who have concurrent and past year use perform like seventh graders who have never used cannabis (a 4-year disadvantage).
  • In combination with other studies, which show an increased risk for the development of psychosis.

3,826 students in Montreal were examined annually over a 4-year period.

The study includes annual assessments with cognitive tests, a starting time in seventh grade, which captures a critical period for both brain development and substance use, and a comparison of cannabis effects with the effects of alcohol.

Cognitive performance was tested with performance-based assessments that are standard for this age group.

The authors of the study concluded that both alcohol and cannabis use increased year over year across the various levels of frequency of use (number of drinks a week), with the exception of daily alcohol use.

They also concluded that the effects of cannabis are greater than those of alcohol.

According to the study, the use of cannabis has persistent effects that are also increased by continued use.

“The results of meta-analyses of epidemiological data (6) have suggested that the risk for schizophrenia among cannabis users is about double the population base rate, at around 2%. The risk could also be increased within individuals by genomic or life-stress-related factors. Although these data suggest that 98% of cannabis users are probably not at risk for schizophrenia, a doubling of risk for any lifelong serious mental illness is clearly a cause for concern.”

Read the results of the study yourself HERE.