These attitudes are normal, certainly, but remain terribly dangerous and, in fact, distressing for parents.
That's certain. At-risk behavior is the leading cause of death among adolescents. But to reassure parents, I would suggest that they remember that they too took risks when they were young, or that at least they did questionable things and that their own parents had no idea! And you should know that, often, teenagers exaggerate, in their head and in their words. From time to time, they like to "plug in" with the risk: "Last night, I drank so much, I do not know how I got back!" Whether he tells you that or you surprise him telling his party to a friend, be careful: there are many "risk scabs" in adolescence. They are not as unreasonable as they say. But the parent's goal will be to take part in the game, staying clear on his position: "I find it silly that you drink."
From when to really worry about his teenager?
There are some signs to be aware of: if he sleeps very badly, if he has self-destructive behaviors ... It's not about reacting to the least of these signs, but rather to to be alerted when they move in bundle and register in the duration. Whether your child has a bad night or one or two piercings is not alarming in itself. But if he lands with ten piercings on the body, there is something to be stopped. More generally, I believe that the major sign of adolescent malaise is the abrupt change in behavior. It is for example a young nice and talented in class who, suddenly, scuttles his schooling and becomes morose. When you do not recognize your child, when you face a misunderstanding mixed with worry, then you need a third.
Do you advise not to wait too long before
to consult a psychiatrist?
Yes. Some, under the pretext that "it's adolescence," let their child suffer. What risk is there to consult? Seeing a psychiatrist for loquats is better than doing an analysis for years! What I advise is first to talk to his GP: he will help the young and his parents to develop the right questions to ask, then the psychiatrist.