I’m a hypocrite ex pot-smoker who dreads my children toking

The largest study ever conducted into the effects of cannabis on mental health has just been published, and it makes a mother’s heart tremble. Teenagers who smoke cannabis are a third more likely to suffer from depression and three times more likely to kill themselves.

Researchers from Oxford and Mcgill universities analysed the results of 11 different surveys, conducted over 25 years and involving 23,000 people. The results also showed a clear link between teenage cannabis use and low achievement, addiction and psychosis.

As my children edge their way towards adolescence, I am surprised to find that drugs are what I fear most. I hate the thought of them clouding their pure, pink, happy brains with a single puff of THC. But how can I counsel them to Just Say No when – like almost everyone of my generation – I am hobbled by hypocrisy?

I smoked pot for almost 20 years. I started at 16, because I wanted to get in with the cool kids at school, and soon discovered that I was rather good at it. I never had a “whitey”, and I rolled beautiful joints: so long and slender they could have dangled from the lips of a Twenties Flapper.

Once, on my year off, I won a spliff-rolling contest in an ashram somewhere in northern India. My competitors – all hardened travellers from Israel or Germany, with blonde dreadlocks and pungent jerkins – passed my winning joint around, cooing over its elegant shape and smooth draw. I could hardly have been prouder if I’d won the Turner Prize.

Unlike alcohol, pot never made me feel sick or out of control. I can’t even say it made me especially torpid. After university, I shot out of the traps faster than many of my contemporaries, getting a job on a national newspaper and clambering diligently up the career ladder.

Back then, cannabis served exactly the same purpose for me that a gin and tonic does now: a relaxant at the end of the day; a way of switching tracks so that my brain could pull into a siding for a rest.

But – and this “but” grows increasingly shrill as my children get older

– I was so, so lucky. Some of the friends I used to get stoned with did end up depressed, paranoid or underachieving.

One or two developed serious mental health problems, including psychosis and schizophrenia. Others graduated to more serious addictions. Two are now dead from overdoses. Although cannabis didn’t kill them, our culture of insouciant drug-taking certainly didn’t help.

And, back then, the drugs were much milder. We smoked hash from Morocco or Lebanon – the same mellow, giggly stuff that got the Flower Power generation making love, not war. But these days the market is flooded with skunk, which is up to 10 times stronger than the old stuff.

Skunk isn’t relaxing: it’s a lungful of the screaming abdabs. The only time I tried it, I felt as if a violent road-rage incident had gone off in my head. I actually took it back to the dealer and lodged a complaint.

The thought of my children smoking skunk fills me with a terror I never once felt for myself. Their fragility is so much more visible to me than my own. “Do as I say, not as I did,” I find myself praying. The hypocrite’s mantra at least has the weight of experience.