Marijuana use in early adolescence may affect verbal IQ

If you start smoking weed as early as 14, it may cause brain impairment in the areas of verbal intelligence quotient (IQ) and specific cognitive abilities by the time you reach 20, researchers warned.

The findings showed that adolescents who start smoking marijuana in early teenage may perform poorly in their language tests or verbal IQ -- related to frontal parts of the brain, particularly those that require learning by trial-and-error.

"The study suggests that the effects of cannabis use on verbal intelligence are explained not by neurotoxic effects on the brain, but rather by a possible social mechanism," said lead author Natalie Castellanos-Ryan, Assistant Professor at Universite de Montreal in Canada.

Those who started early are also less likely to attend school and graduate than non-smokers, which may further affect opportunities to further develop verbal intelligence.

The effect was also seen on cognitive tests as well as on short-term memory and working memory.

"In addition to academic failure, fundamental life skills necessary for problem-solving and daily adaptation [...] may also be affected by early cannabis exposure," Castellanos-Ryan added.

In the study, published in the journal Development and Psychopathology, the team looked at 294 teenagers who completed a variety of cognitive tests at ages 13, 14 and 20 once a year from ages 13 to 17 and again at 20.

--IANS

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