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‘How do I stop my 18-year-old son smoking so much weed?’

Ask the Expert: The first step is to get informed about the risks of drug taking so you know what to watch out for and how you can respond


How do I stop my 18-year-old son smoking so much weed? It’s everywhere and so easily accessible. He doesn’t drink at all and argues that weed is safer than drinking, but I’m so worried about his health. He still does all of the things he loves and is really outgoing and motivated, but I’m worried it’s a slippery slope.


As a parent, it is understandably a great worry when your teenagers get into the habit of using drugs. Even when they are over 18 or even older, and should be making their own decisions, you can still worry. Indeed, the risks for young adults regarding drugs are significant and this is at a time when you have much less influence as a parent.

In thinking how you can influence your son, the first step is to get informed about the risks of drug taking so you know what to watch out for and how you can respond. Your son has a point when he says that the risks of alcohol use could be greater than cannabis/weed. Research suggests that both are potentially addictive and “gateways” to excessive drug use. Both come with significant, though different, health risks that depend on the frequency and context of use.

For example, moderate alcohol use is less risky than binge drinking or “getting drunk at the weekend” and some of the negative impacts associated with weed are linked to inhaling smoke [like cigarettes] and avoided in using edibles. Uniquely, weed is illegal which means that your son is at risk of prosecution when he buys it or has it in his possession and this could harm his career or prospects. (A good online article exploring the relative risks of alcohol and weed.)


Negotiating with your son

It is good that your son is talking to you about his weed use. Many teenagers keep it hidden from their parents and stonewall them in discussions. Come informed when he raises the issues and keep your focus on his safety and wellbeing. As well as discussing facts, listen to what he gets out of using weed (for example, relaxation) and explore other ways he can achieve these goals.

Be careful about over-criticising his choices and instead focus on your care for him. For example, you might say “You are entitled to your view, but as your mum/dad, I disagree. I love you and I don’t want you to be using weed. I am worried about your health and I want you to be safe and well.” As you discuss issues, your initial goal might be to negotiate with him to reduce his use and/or ensure he uses safely.

Choose ultimatums carefully

Some parents in a panic resort to ultimatums around drug use – “If you continue to use weed, then you have to leave home.” Such ultimatums are unlikely to be enacted and, if they were, they can put your teenager at a greater risk and break down communication between you. However, some well-thought out limits and rules can sometimes help with young adults in the home. For example, you might insist he does not use in the house or he uses only in his bedroom alone or that if he uses, he keeps it to a smaller amount, and so on.

Rewards or incentives might help also. For example, you could encourage him to reduce or stop his drug use and agree that each week he achieves this you will put money aside for him for a special holiday or trip in six months. You could also encourage him to seek counselling to explore his drug use without yet making a full decision to stop.

Build your relationship with your son

Despite your son using weed and your disagreement with this, it is important to keep the lines of communication open between you. The more warm and connected your relationship is with him, the best chance you have of influencing him to be safe.

So try not to make his drug taking the “only issue” between you, and continue to have a normal parent-teenager relationship with him. Find ways to reach out to him so you share time doing fun things together and have time to talk about all the things going on in his life.

Identifying risk factors

At the moment, your son seems to be doing well despite his weed use. As you say, he is motivated, outgoing and does all the things he loves. Keep a close eye on his wellbeing over time. If he becomes withdrawn or demotivated or starts cutting himself off, then these are warning flags that he is not coping and you may have to reach out to provide more support.

The HSE runs a drugs and alcohol freephone helpline on 1800 459 459 from Monday to Friday between 9.30am and 5.30pm, or you can email at any time on The HSE could provide you with more individual options to help your son. It will also be able to provide you with lists of face-to-face counselling services should you or your son wish to avail of these.

  • John Sharry is clinical director of the Parents Plus Charity and an adjunct professor at the UCD School of Psychology. He is author of several parenting books including Parenting Teenagers.,