This week a report has been released illustrating a new facet of potential harm from cannabis. In a long-term study (carried out by scientists in Otago, at Duke University, USA and King’s College London), IQ and cannabis use were monitored over 25 years from age 13 to 38.
Of particular interest, their study of over 1000 subjects included teenagers in whom IQ was checked before any cannabis exposure. Around 1 in 7 reported being regular cannabis users, 1 in 20 doing so at least weekly before the age of 18.
What did the investigators find? With no cannabis history, there was a small decline in IQ. However recurrent cannabis use was associated with an 8 point decline in IQ, comparable to that seen in early dementia. Importantly, this decline in IQ was particularly marked when cannabis use began during teenage years. A further concern was that stopping cannabis use did not lead to recovery of the IQ loss. Commentary on the results has ranged from concluding that cannabis is harmful in teenagers but safe in adults, to more cautious notes that adolescent brains appeared more vulnerable to cannabis, without providing carte blanche for longer term safety of cannabis use in adults.
I been knowing this because weed heads are fucking dumb.