What are the problems with defining the start and end of adolescence? Why do these problems exist?

Hi. The answer to this is a bit complex so you can find it under the explanation

Explanation:

Everyone acts differently; some people face many emotional, physical, and mental problems during adolescence, and others do not experience these things.

In fact, the problems defines this period are various, since the definition of personality, also problems relationship the sexuality, drug use, alcohol, what career to follow, between others.

The most of problems appears of uncertaints that come in mind of young man who is becoming an adult.