Researchers from McGill University conducted a study that looked at how the age one starts using marijuana is related to later health problems, both mental and physical. The results were stunning. They found that frequent marijuana use starting early (before age 15) is associated with a 51% higher chance of mental health problems. For physical health problems, a whopping 86% higher chance. “Frequent use” for these researchers meant at least once a month: Just imagine how much worse these results would look if they isolated the daily or more-frequent users, especially since the earlier you start, the more you use. Marijuana is terrible for you no matter what metric you use: there’s just no avoiding its harms.