Marijuana may up psychosis risk in teenagers

 Toronto, July 7  (IANS) Daily consumption of marijuana  may increase an adolescent's risk of having recurrent psychotic-like  experiences by 159 per cent, according to a new study.The  psychotic-like experiences include the experiences of perceptual  aberration -- for example feeling that something external is part of  their body -- and thinking that they have been unjustly badly treated."Our  findings confirm that becoming a more regular marijuana user during  adolescence is, indeed, associated with a risk of psychotic symptoms,"  said lead author Josiane Bourque, doctoral student at the Universite de  Montreal (UdeM) in Canada."Although they may be infrequent and  thus not problematic for the adolescent, when these experiences are  reported continuously, year after year, then there's an increased risk  of a first psychotic episode or another psychiatric condition," Bourque  added.The findings, published in the Journal of Child Psychology  and Psychiatry, revealed that individuals who go on from consuming  marijuana occasionally to abusing the substance once a week or as often  as every day, may be at 159 per cent increased risk of developing  psychosis-like experiences.Marijuana use reduces a person's ability to resist socially unacceptable behaviour in response to a particular stimulus.An  increased risk of depression as a result of frequent marijuana use is  thought to be behind psychosis' onset, the researchers said."Our  results show that while marijuana use is associated with a number of  cognitive and mental health symptoms, only an increase in symptoms of  depression -- such as negative thoughts and low mood -- could explain  the relationship between marijuana use and increasing psychotic-like  experiences in youth," Bourque said.These findings have  important clinical implications for prevention programs in youth who  report having persistent psychotic-like experiences."While  preventing adolescent marijuana use should be the aim of all drug  strategies, targeted prevention approaches are particularly needed to  delay and prevent marijuana use in young people at risk of psychosis,"  noted Patricia Conrod, professor at UdeM.