The Hollywood actor plays a man struggling with dark moods who uses a glove puppet as an outlet for his feelings, and Gibson was able to empathise with his character because he has struggled with the condition himself.
And the Braveheart star is convinced learning to understand the disorder helped him battle his own demons.
He tells Deadline.com, “Depression is like that. It’s somewhere one can be caught. You can get stuck there. Initially, it does stem from a certain amount of egotism… What does it do to everyone around in the family? It is an illness. It is a disease. And, I think there is a better understanding of it.
“A guy said to me one time, something really profound, and it’s so simple. It’s that depression lies. It’s a liar and you have to shut it down. There is nothing that alleviates it more than going out and doing something for someone else. It’s almost like instant healing. Get away from yourself.
“People can’t even get out of bed and it gets really severe. I’ve never been at that stage. Everyone goes through low and high and low and high and some people are blessed to be created on an even keel all the way through – but not me.”