Worried about someone else's use?
Most of this site is written for the person who uses. This page is for you: the partner, parent, friend or family member watching someone you care about, and not sure what helps. You have more influence than an ultimatum, and less control than you'd like. Here's what the evidence and experience actually point to.
Loving someone whose cannabis use worries you is its own kind of hard: you can see it, you can't fix it, and most of the obvious moves (pleading, policing, big confrontations) tend to make things worse, not better. What follows isn't about controlling them. It's about the things that genuinely shift the odds, and about not losing yourself in the process. To weigh the risks in proportion, especially if it's a young person, Cannabis & young people and the honest risk picture help.
Is this worth worrying about?
Start by separating use from a problem, because they're not the same thing and treating every joint as a crisis burns your credibility fast. Plenty of people use cannabis without it running their lives. The things actually worth worrying about are patterns: use that's climbing, that's become daily or first-thing, that's eating money they don't have, or that's visibly costing them their work, studies, relationships, motivation, mood, their health. A useful question isn't "do they use?" but "is it taking more than it gives, and is it still growing?" If you want a sense of where their use sits, the site's own self-check is built for the person using, but it can help you understand the picture too.
What actually helps
There's a well-studied approach to exactly this situation, a family member wanting to help someone who isn't asking for help, and it points away from confrontation and towards patient, positive influence. STRONGEvidence strength Community Reinforcement and Family Training (CRAFT) teaches concerned family members how to change how they respond day to day: reinforcing sober behaviour, stepping back from behaviours that cushion the use, communicating without conflict, and looking after themselves. It's one of the best-evidenced options for helping someone who is refusing treatment. Key evidence: reviewed in Roozen, de Waart & van der Kroft (2010) and summarised by the American Psychological Association: CRAFT gets substantially more treatment-refusing people into treatment than traditional confrontational "intervention" or support-only approaches like Al-Anon, while also improving the wellbeing of the family member, whether or not their loved one ever engages. The point: the approach that works best is also the kinder one, and it helps you even if it doesn't immediately change them.
In practice that looks like a few things. Pick your moment. Raise it when they're sober, calm and not cornered, not mid-argument or mid-high. Lead with what you see and feel, not with a verdict: "I've noticed you seem flat lately and I miss you" lands very differently from "you're a stoner and you need to stop." Notice the good. When they're engaged, present, doing well without it, let that be seen and valued. People move towards what feels good, not away from what feels like nagging. And make help easy to reach for: know what's out there before they ask, so that the day they're even slightly open, the next step is right there rather than a mountain to climb. The whole of the Quitting toolkit on this site is built to be that low-friction next step.
What tends to backfire
The instinctive moves are usually the counterproductive ones. Ultimatums and blazing rows tend to entrench people and push the use underground rather than end it. Constant monitoring, searching and checking up corrode trust and cast you as the enemy, which is exactly the wrong role. Rescuing them from every consequence, covering for missed work, paying the debts, smoothing it all over, quietly removes the friction that might otherwise prompt change. Letting reasonable, safe consequences land is not cruelty, it's honesty. And the dramatic surprise "intervention", despite its reputation, has a weaker evidence base than the calmer, ongoing approach above. Being consistently, warmly present beats one big confrontation almost every time.
If it's your child
If the person is your teenager, the stakes feel higher and the ground is different: a younger, developing brain, and a relationship where you still set some limits. The same principles hold (calm over confrontation, connection over surveillance), but you don't have to navigate it alone or work it out from first principles. In the UK, FRANK has clear guidance for parents, and family-support charities (below) work specifically with parents in this exact position. Keeping the relationship open, so they'll still talk to you, usually matters more in the long run than winning any single argument about it.
Look after yourself too
This is the part people skip, and it's not optional. Worrying about someone else's use is genuinely draining, and you can't pour from an empty cup. Your own steadiness is, practically speaking, one of the most useful things you can offer them. You're allowed to set limits on what you'll tolerate in your own home and life. You're allowed to have a life that isn't organised around their use. And you're allowed to get support for yourself, separately from whether they ever do. That's not giving up on them, it's staying well enough to be there for the long haul.
UK support
You don't have to hold this on your own. Several UK organisations exist specifically for families and friends affected by someone else's drug use. Adfam supports families affected by drugs and alcohol and can point you to local family services. The NHS guide for families of drug users is a clear, practical starting point. FRANK offers free, confidential, non-judgemental information and a helpline, for you as much as for them. And if and when the person you care about is ready, this site's Quitting toolkit and Harm Reduction pages are here for them.