Dr. Amen has a show on PBS when they do the "pledge drives".
He said on TV that drug abuse including many things make a brain with holes in it.
The pictures he had on TV were more dramatic, and he even said he made thousands of posters and donated them to schools, for anti-drug use educational purposes.

His books go into more detail. But long term or high dose opiates was one I do remember. MJ was included...and even nicotine!

The picture he used on TV showed huge and many areas of no activity! Like Swiss Cheese.
You might find his book in the library, like I did.

http://search.barnesandnoble.com/Cha...ange+your+life

This is really really an eye opening book .. it even goes into couples counseling when spouses have different brain maps and react to things in ways to make conflict.

The biological things of course, are the real eye openers!