Teenage cannabis users risk damaging IQ
A major study has concluded teenagers who get hooked on cannabis risk long-term damage to their Iqs.
Attention and memory are also harmed according to the US-led research.
One thousand people have been studied and scientists conclude the most persistent cannabis users suffer an average eight-point decline in IQ between adolescence and adulthood.
There is no evidence of similar problems for those who take up the drug as adults.
The results are significant because while cannabis is often linked to schizophrenia - a relatively rare condition - this seems to be the first firm evidence of its effects on everyday functioning.
