London: Children who start smoking cannabis before turning 15, struggle with mental exercises, doing much worse on tests than those who take it up later in life, a new research has warned.
Research carried out at the Federal University of Sao Paulo in Brazil looked at the mental functioning of 100 cannabis users after around ten years of consistent use, and almost 50 non-users, reports the Daily Mail.
They found 49 ‘early’ users whose habit began before the age of 15 were much worse at sustained attention, impulse control and executive functioning.
In a card-sorting test they made many more errors than 55 youngsters who got the habit later and 44 people who had never taken the drug.
Lead researcher Dr Maria Fontes said: “We found that early-onset, but not late-onset, chronic cannabis users had deficits in their cognitive functioning.
“Adolescence is a period in which the brain appears to be particularly vulnerable to the neurotoxic effects of cannabis.
“The brain before the age of 15 is still developing and maturing, so exposure to cannabis during this period may be more harmful,” she added.
The study has been published in the British Journal of Psychiatry.