Answer:
Step-by-step explanation:
Teens are very vulnerable to peer pressure. If a good friend of your does drugs and sort of pressures you into doing it, you will likely do it cuz your friend is pushing you and you also don't want to be called a downer (or uncool)
If other "cool" kids are doing something and you want to be part of the group, you are sort of pressured into doing stuff like this to be part of the group.
Drug abuse can also come from observation. If your neighborhood, your parents, or your guardians are into drugs, chances are you might get involved with it as well.
Finally, teenage years are rough years in term of mental health (as you are dealing with hormonal and physical changes), thus people can have anxiety, bad self image, mental disturbances etc. To alleviate these kinds of stress, teens might abuse drugs.