Youngsters addicted to cannabis are at increased risk of damaging their IQ and may show signs which are usually seen in early Alzheimer’s, warned researchers from the Institute of Psychiatry at King’s College London. The study identified a noticeable drop in intellect in those who started using cannabis in their teens and continued to take it for years subsequently.
A team of international researchers put more than one-thousand teenage boys and girls through a battery of IQ tests. The same test was performed after twenty years when those boys and girls reached the age of thirty-eight and any differences were noted. They were also asked every few years if they had taken cannabis and, if so, how often.
The study findings showed small drops in IQ in those who never or rarely used the drug and in those who had started to use it a lot as adults. But, boys and girls who became addicted to cannabis in their teens, their IQ dropped by an average of eight points.
The study analysis also found that those who used the drug persistently from their teens did worse on a memory test used normally to spot revealing signs of dementia. These findings important because while cannabis has been blamed for relatively rare mental health problems such as schizophrenia, but, for the first time evidence show causing damage on everyday life.
Prof Terrie Moffitt from the Institute of Psychiatry, explained study has shown that IQ is a strong determinant of a person’s access to college education, their lifelong total income, their access to a good job, their performance on the job, their tendency to develop heart disease and even early death.
Individuals who lose eight points in their teens and twenties may be disadvantaged, relative to their same-age peers, in the most significant aspects of life and for years to come, added Prof Moffitt. The study was published in the journal Proceedings of the National Academy of Sciences.