Your Mind & Use
The risks that aren't about your lungs, and the honest self-awareness that keeps them small.
Most harm-reduction advice is about the body: routes, doses, mixing. But cannabis's more serious risks are often about the mind, and they're quieter and slower, which is exactly why they're worth watching for deliberately. None of this is scaremongering. It's the stuff that lets you catch a problem early instead of late.
Some people have more reason to be careful
The mental-health risks of cannabis aren't spread evenly. The link with psychosis is real, dose-dependent and strongest with frequent, high-potency use, and it's concentrated in people who are already vulnerable, particularly those with a personal or family history of psychosis or serious mental illness. If that's you, the honest harm-reduction position is that you have more to lose and less predictable ground, and that lower-potency, less-frequent use (or none) is the sensible call. Age matters too. The younger the brain, the higher the stakes, because it's still developing into the mid-twenties. The evidence behind both is laid out in Long-Term Effects and Higher Stakes.
The anxiety loop
The most common mental-health snag isn't dramatic, it's a loop: cannabis calms anxiety in the moment, but for a lot of people it raises baseline anxiety over time, so you end up using to relieve an anxiety the using is partly keeping going. If you notice you're more anxious, more on edge or more low between sessions than you used to be, that's worth taking seriously as a possible sign the cannabis is part of the problem rather than the solution. It isn't proof, but it's a prompt to test it with a break.
Honest self-monitoring
The single most protective habit is simply staying honest with yourself about the why. Using to enjoy something is a very different thing from using to not feel something, and the slide from the first to the second is where trouble usually starts. A few questions worth checking in on now and then: Are you using more to feel normal than to feel good? Is it the only way you can relax, sleep or cope? Has it stopped being fun and become just a thing you do? Answering yes doesn't mean disaster. It means pay attention, because the mental side of problem use creeps rather than announces itself. That's the subject of Is It a Problem?, and if any of this is tangled up with low mood or anxiety, Your Mental Health and a GP are good places to take it.