They have a high desire to be accepted. They smoke to fit in and be accepted. Whether it is to reduce appetite so as not to become over weight or just because it is that others are doing it.
You see it every where that they want to be accepted and is why they criminalize or try to criminalize anything that does not support their self image.
In other words they are not right in the head and can not accept their selves.
You know what they say about guys that smoke