I agree with the previous posts on the issue.
as well,
For some it has to do with life being a pain in the gulliver

. And this pain is the product of an individuals experiences from childhood to present. And this individual finds temporary relief buried in their drug induced 'high's'...unfortunatley it is not a fix nor a remedy.... I think a lot of people think they find 'love' for their first time whilst in a state of 'high'. They didn't get it from their pair of creators (parents) and it has created a void in their hearts...thus a void in their being...they find a temporary fill of the void from the drug...they become addicted to the drug...novelty wears off and the 'high' isn't the same anymore but they continue attempting at it in hopes of finding that honeymoon moment again (increasing dosages, increasing intervals between use), only to fail, and self destruct.
thank the parents.
(disclaimer: not my story...just an ideal from observation)
I think the individuals that use and abuse substances to the point of destructiveness are the ones that fall in this category most of the time.
The person that is happy and curious and takes interest in experimentation is usually pretty healthy about their usage.
There are many reasons why a person may become fascinated with the 'high'.
I personally try to utilize my 'high' times for self-exploration, spirituality, and finding deeper connections with other beings of life through the alternate eyes that are granted by certain substance induced states of mind. And I don't find the benefits of this approach to getting 'high' as being temporary because they can be learned from and applied to the same things in a state of sobriety...
pushing yourself into the right frame of mind is the trick....whereas with a drug, you are taken to that state of mind involuntarily.
Imagination is a powerful thing.