ACTRESS JENIFER LEWIS used to think she was pretty good at keeping her demons hidden.

Lewis, 50, who co-starred in Tyler Perry's "Madea's Family Reunion," was often the proverbial life of the party - the larger-than-life diva not the least bit shy about climbing onto a tabletop to blast out a song as admirers gathered around and declared her "fabulous."

But there was a frightening flip side to her life. She'd explode in overwhelming bouts of anger at the slightest provocation. Once she flew into a tirade after a perceived racial slight at a nail salon. In another incident, she chased down another motorist in a road-rage incident, endangering her life as well as others in the area. And, inevitably, there were the crying jags and dark moods that she couldn't shake. Depression would linger for weeks.

"There were a few who knew," she told me last week. "I did this Christmas party once and there were psychiatrists in the audience. Girl, I had people doubling over, crying. But there was one psychiatrist in that party who came over to me after the performance. She said, 'You're very talented but there's a lot of pain underneath what you're saying.' . . . She recommended a therapist to me and I've been with that therapist for 17 years."

Like 5.7 million Americans, Lewis suffers from bipolar disorder, a mental illness marked by severe mood swings such as the one in which Lewis impulsively purchased a $2.3 million mansion. Actress Sinead O'Connor has admitted to suffering from the disease as has Maurice Benard, from ABC's "General Hospital." Some experts say singer Phyllis Hyman killed herself during a depressive episode.

During a manic phase, sufferers typically experience exagerrated feelings of importance and optimism. But then come the lows which are marked by prolonged bouts of sadness and hopelessness. Although the exact cause is unknown, eperts attribute the disease to some sort of imbalance of chemicals in the brain.

"Why the hell should you be ashamed of a chemical imbalance?" said Lewis, who'll be in Philly Friday to participate in a mental health conference called "Breaking the Silence: A Summit on Behavioral Health within the African American Community" at the Pennsylvania Convention Center.

Shame, she pointed out, is what keeps people from seeking psychiatric help as she did.

"I can tell a bipolar person from down the street. Usually, it's because that person's head is low or else they're hollering and screaming . . . they're usually the loudest person in the room or the most angry person in the room.

"I've got a girlfriend who's so bipolar," she went on. "When she laughs, it's louder than anybody else. When she's depressed, you won't see her for five days."

The disorder is treatable with medication but even after undergoing talk therapy, Lewis resisted chemical intervention for years, fearing she'd lose her creative edge.

"Don't you ever try to take that high from somebody that's manic," she said. "They are addicted to the high."

She used to think, "I'm Jenifer Lewis. I don't need that s---. Are you kidding? Everybody wants to be high. We wake up high. Just lit. Bouncing out of bed and just running amok."

But without medication, her behavior was erratic.

"Your sexual desire is heightened constantly. Your energy is boundless until you hit that brick wall or that dark cloud and you're sent spiralling into the abyss and it takes weeks or months to come out of it. It's staggering."

Lewis sees examples everywhere of people struggling with bipolar disorders.

"There's such a denial in the African-American community. It's usually [seen as] that crazy aunt and that crazy uncle . . . 'Uncle Jimmy lives in the attic.' Or 'Aunt Mary lives in the basement and is laughing loud.'

"When you don't see these people come out, they are undercover and they are depressed," she said. "When you see people speeding, they are speeding in their minds. Who is paying attention? Who's listening to people who are screaming a silent scream for help?"

A lot of times, people who commit a crime or do something else drastic actually are seeking help.

"I'm speaking directly to us - anything to get people to wake up. I go for the jugular. I'm talking about real damage that comes from people who are bipolar. The damage that is done. The denial is there," said Lewis, who earlier this year disclosed her mental-health struggles on "The Oprah Winfrey Show."

Acknowledging that a mental-health issue exists is a first step.

"You get in there you find out it has nothing to do with your daddy or your friends, but it has everything to do with you. Go in there and tell yourself the truth."

With her disease under control and three new movies coming out, Lewis is sage-like when it comes to sharing her views about bipolar disease.

"You have to find something you love. You have to, because it will balance the madness," she said.

"If you want to put your energy into something, put it into being well . . . getting well so you can live. We don't have to suffer. This is America. I don't want to hear that you can't afford it." *

Jenifer Lewis will perform the one-woman play she wrote her illness called "Bipolar, Bath & Beyond" at 6:30 p.m. Friday at the Pennsylvania Convention Center during "Breaking The Silence 2007," a summit on behavioral health within the African American community."