Substance abuse on application..?

I have a question on whether it would be wise or not to mention my struggle with substance abuse on my application/ letter of intent. I believe it may be beneficial, however others have advised me against it (None of which are pre-med students or advisors). There are many factors involved in this: 1) I am a non traditional student, who has an atrocious transcript for my first two years after high school at a state college (consisting of many F’s and W’s). Followed by another 4 year gap in... SUBSTANCE ABUSE ON APPLICATION..?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums