Few months ago, one of my (lost!) friend made an interesting comment that: "For manic depressive people, sometime mania is mentally so pleasurable that they are willing to take bouts of depression, instead of taking medicines which keep them always numb"!
In same regards, few weeks back I had an interesting argument with a colleague on Sir Arthur Conan Doyle's character Sherlock Holmes who was addicted to intravenous cocaine, and probably performed well due to it.
Though definition of addiction is relative, but it can be anything - golf, online games, alcohol, gambling, pornography, diet coke, shopping etc. etc. etc. - and right or wrong - some people thrive on it and their brilliance only shine due to it - as it energizes their mental activity. They feel dead without it.
Now I am way less judgemental for people who have any such weird habit.
As Shakeel Badayuni said
nashe main hun lakin mujeh ye khabar hai,
ke is zindagi main sabhi pii rahe hain
Kisi ko mile hain chalakte piyale,
kisi ko nazar se pilayi gai hai
Kisi ko nasha hai jahan main khushi ka,
kisi ko nasha hai gam e zindagi ka
koi pi raha hai lahu aadmi ka
har aik dil main masti rachaii gai hai