Cannabis is responsible for 91 per cent of cases where teenagers end up being treated for drug addiction, shocking new figures reveal...The findings also back up academic research, revealed in The Mail on Sunday over the past three years, that skunk is having a serious detrimental impact on the mental health of the young. At least two studies have shown repeated use triples the risk of psychosis, with sufferers repeatedly experiencing delusional thoughts. Some victims end up taking their own lives.