But now when he looks back, he wishes that at 18 - he could have started living his life much earlier.
"When I was growing up I felt like a complete freak. I wish I had known that there were a lot of people out there like me, feeling the same way, the Sun quoted Depp as saying.
"I even felt weird at five. At the age of 12, I felt it was me against the world.
"I locked myself in my bedroom and played my guitar. It seemed as if I was in there for two or three years!
"It took years for me to feel comfortable with myself. I do not have to pretend any more about who I am and do not have to portray any image which is not myself.
"I wish I could have come to terms with who I was much earlier in my life, but I am sure a lot of people would say the same thing. I was able to play characters who were considered freaks to outsiders. But, to me, they were always real people. They felt love, anger and loneliness.
Depp admits that meeting the love of his life partner Vanessa Paradis, 38, and then becoming father to children Lily-Rose, 11, and Jack, 9, made him realise what the important things are in life.
"We need to rethink how to live. I wish I could have known at 18 that I would one day live in France and meet the love of my life.
"Having kids also changed my life for the better. Being with my family makes me happy - and shows in my face. I feel young and happy,” he added.