With David Letterman's final show last night, I wanted to share what I admire most about him — that he was open about his battle with depression.

While Letterman rarely opens up about his personal life, I am glad that a couple years ago, he decided to talk about this.

AP photo - Letterman's final show

In an interview with Oprah, he said, "I never knew what depression was. ... (Depression), I'm telling you, is — you get on an elevator and the bottom drops out. You can't stand looking at the sunlight, you can't wait to get back in bed at night."

He said he went through this crippling depression for about six months and describes it as "seeing the world with 20/20 vision."

"It's a sinkhole. People who have gone through it know exactly what I'm talking about."

In another interview, Letterman said, "For years and years and years – 30, 40 years – I was anxious, and hypochondriacal, and an alcoholic, and many, many other things that made me different from other people.”

With the help of medication, which Letterman said he was reluctant to take, he pulled through his depression. And he now has compassion for others who are battling this.

"I always thought, 'Aw, you're depressed? Go do some push-ups and you'll feel better,'" he said. "But it's not that."

I have found that many times, the people who seem happiest are the ones who have the biggest inner demons to fight. They use jokes and a goofy demeanor to mask how they're really feeling.

But I believe that, in order to overcome this, you first have to admit it. By hiding it, you're giving power to your depression,
you're not allowing others help you and, even more importantly, you're not helping yourself. By hiding it, you're not treating it as exactly what it is — a disease.