Knowledge can be a burden, but it's only one type of burden that we as human beings face on a daily basis. Any one who works hard has similar burdens that can lead to bad habits forming in the long run. Don't believe that you have to be smart in order to abuse. It can happen to anyone if they are not careful.
The theory is that those of higher intelligence often seek out new experiences. Because of this, those with higher IQs are more likely to try different substances. This increases their risk of becoming addicted. Additionally, those who develop verbal skills earlier tend to perform better academically and have higher social interaction. Those who spend more time with their peers are often exposed to things like alcohol and drugs at an earlier age. Again, this factor increases the exposure risk as well as the risk of becoming addicted. Another factor to consider: Those who have higher IQs are more likely to attend college. Those who attend college are much more exposed to drinking and a subculture that accepts and promotes heavy drinking. Take a look at this article: http://www.newrepublic.com/article/115802/intelligence-and-drinking-studies-say-theres-correlation
I think most drunk people tend to be more creative and intelligent because whenever they are under the influence of alcohol, their inhibitions have somehow released. They don't have limitations anymore; they just want to create and create.
Addiction makes you weaker, not think rationally, alters your perspective on many levels, and do things you regret afterwards. So, it doesn't make people smarter at all; it actually makes them more stupid (because you have to be a little dumb to abuse alcohol or any other kind or drug). Yes, it may make you more creative, but being so without the intervention of any substance is called real intelligence.