Since his childhood, actor Richard Dreyfuss has struggled with bipolar disorder. But it took many years for the 66-year-old to fully understand what it was he was battling.

"I didn't know it was a manic state," he explained on the TODAY show Tuesday. "I just thought I was really happy, and everything that was bad, I turned to good."

But those around Richard knew that something was off. "Every once in a while, when I was talking, I would find myself getting up and talking louder and faster and louder and faster and louder and faster, until my friends would say, 'OK, OK. Let's get the big circus cables and throw them around his ankles and pull him gently back to Earth," Richard recalled.

He shared that it wasn’t until he realized he couldn’t rid himself of the disorder that the shame began to slip away.

"It took away all of my guilt because I found out it wasn't my behavior — it was something I was born with," he said. "I didn't feel shame or guilt. It's like being ashamed that you're 5-foot-6 or something. It's just part of me."

The actor, best known for his roles in “Jaws” and “Close Encounters of the Third Kind,” hopes that the stigma associated with bipolar disorder will be diminished once people understand what it is.

"Stigma is silly; stigma is stupid; stigma is what other people think about you. I, first of all, don't know anyone who's normal. Everybody's got something, and I come from Hollywood so no one even argues the point. 'Stigma' is a word that should be kicked away —because it's a condition," he said.

Richard's disorder has inspired him to become an active advocate for the Hope for Depression Research Foundation, which aims “to fund innovative scientific research into the origins, diagnosis, treatment and prevention of depression and its related disorders.”