Heath Ledger and the Joker - Did the role lead to his ultimate demise?

Now I've never really checked out CNN's iReport but today I wanted to see what people where saying about his performance in the Dark Knight. This gave me a deeper appreciation for Heath.

Dark Knight; Immediate Afterthoughts of a Man and his Acting.
Posted by: citnos
I come from a good home. I went to church as a child and was, for the most part, a good kid. I've done some bad stuff in my lifetime, but I'm a good person. I like to think that most people are, some way, good in their hearts in there. Some people are more good than others. Some people know how to pretend they're not, better than others. Some people know how to be two completely different people; you see that a lot online nowadays. Lots and lots of people don't understand what the big deal is about being two people at once. It's just pretend, right? I mean, it should be that simple, right?

I don't know the man. Before he died, I had to go on Youtube to remind myself what movie I had seen him in.

In some... convoluted way... in some weird sense... anyone with a good heart in them... when you go see this movie...

You'll know why this role killed this man.

I think... knowing what this movie did to a good boy... that this movie is the darkest, most disturbing movie I have ever seen. I can't even imagine the nightmares this movie must have given this man, to pretend to be this person, this heartless person... I know, it's just a movie... and it was a good movie, possibly one of the best movies I've seen in a long time... however...

This was not his role, at all. He did a superb job, and it's a shame that he did so well, it killed him.

R.I.P. Mr. Ledger. Goodnight.

EDIT: Yes, I'm aware that drugs are what ultimately killed Heath. That's the physical aspect of this. But let me paste in here what I responded to my first wonderful comment pointing this out to me.

Do you have any idea why he was taking those medications though? His friends and family have come out and said that this role was causing him nightmares, so bad that he wouldn't sleep for days on end. Even Jack Nicholson knew why he died when he found out about his death. It takes a specifically skilled type of person to disassociate yourself for a role like this. By no means am I saying that Ledger was 'unskilled', because it's clearly obvious that he played this role perfectly, even moreso than Nicholson, I think, however, it consumed his conscious. He took a giant leap from one side of acting to another, from the good boy to the ultimate supervillian, and while he did it flawlessly, his psyche wasn't ready for it, I don't think, as evidenced by the fact the it was causing him to resort to drastic measures just to induce a natural bodily function such as sleeping. This isn't an actor who had a long-standing drug or alcohol problem that just got out of hand. This role made him choose between sleeplessness and drugs to knock him out, and any person out there who suffers from insomnia for any reason knows that the normal human being will eventually cave and take something to sleep. It was so bad on him that he accidentally killed himself just trying to get some shuteye.

I also wanted to share a quick thought my friend and I were mulling over... I'll bet the original DC Comic authors of the Batman series never thought that the character of the Joker would honestly kill a real man. Think on that. Her response is this:

"I have thought about that. A character so twisted, so depraved, so truly EVIL, that he actually ended the life of a real human being. That was not lost on me. How many other people will figure that out though? I believe if the devil were not a religious entity... he would BE the Joker. The Joker IS the Batverse's Satan."