I know and once talked to a guy who was in my school but had left to join another school nearer to his place. On conversing I got to know that he was heavily into drugs, and used to smoke and drink a lot. His parents caught him once and were cool enough to explain him why and how he should stop doing this. Since then, he’s avoided all phone calls of his friends who ask him to smoke with them, and has been very strong. I’m happy I met such a resilient person who was able to get over this.