I think it was a slow, gradual letting go of life after he and Michelle broke up. And I do wonder if playing the Joker might have had something to do with their breakup. Heath was perhaps too sensitive an individual to get caught up in the profound darkness of a character like the Joker. It was like a moth attracted to, but getting too close to the flame. He couldn't find his way back and when Michelle walked out with Matilda, he started a slow spiral down. He was desperate for sleep and got lackadasical about his own well-being. You can see how unkempt and dejected he looked in those few months leading up to his death. He was lost to himself. I have heard that he was a very stubborn individual and I would suspect that those close to him tried to help but if he didn't want help, it was a waste of time.
I don't think he intentionally decided to end his life. I just think that the circumstances led him to the edge and he rolled off before anyone could catch him. A horrible loss for those who loved him, especially little Matilda and for those of us who thought the world of him as an actor at the top of his game. Rest in peace, Heath. We know you would never have intentionally left Matilda. You just got caught up in something that swallowed you up. We miss you so very, very much.



