Earlier this year, two tech entrepreneurs, Aaron Swartz and Jody Sherman, committed suicide independently of each other. Both faced incredible pressures. And both suffered from depression.

It's not a topic the start-up community understands well. After all, this is the very culture that turned the chestnut "pick yourself up by your bootstraps" into a much-celebrated verb. Admitting you struggle with depression is like admitting you can't reach your bootstraps. It's assumed that successful people can just "shake it off."

But that's not how it works.

I know. I've struggled with serious bouts of depression three times in my life. I'm not talking about a series of miserable days or struggling through the pressure and stress of a failing company. I'm talking about months of feeling emotionally drained.

My latest episode began in January and lifted only in May after months of feeling completely exhausted. In the fall, I was logging 80-plus-hour weeks on a regular basis, traveling most of the time, trying to recover from a bike accident without taking any time off, and sleeping poorly. I wasn't running regularly, which is usually how I get time alone. And in an alarming health scare in October, I wound up in the hospital for surgery to remove a kidney stone.

By January, I had slipped into a deep depression. The joy went out of everything. I spent February through April prying myself out of bed, going through the motions at work, and just waiting to crawl back into bed again.

This is what depression feels like. I'm lucky in that I have an incredible wife, friends, and colleagues who gave me space and simply listened to me, without judgment. My depression eventually lifted, as it has twice before in my life.

With time, I've become more aware of how these cycles work. For one thing, I've noticed that often my most creative moments come on the heels of a depressive episode. I don't think this is a coincidence. Each time it happens, the days get lighter once I finally take steps to simplify my life.

I make time and space to care for my mental health. I stop setting my alarm for 5 a.m. and let myself sleep until I wake up naturally. I observe digital Sabbaths in which I stop checking email, keeping up with the news online, and checking into Foursquare. I travel less. I read and run more.

In other words, I do all of the things that the prevailing start-up culture tries to squeeze out of my life. And as a result, I'm far more productive in the business of building and investing in companies.

I've heard from many fellow entrepreneurs and investors who have confessed to feeling the same way. Here's the rub: Failure has become OK--it's even a kind of street cred--as long as you can write the postmortem blog post about your heroic pivot.

But depression carries a stigma. Most of the success stories we hear involve an entrepreneur who pushes himself beyond his physical and emotional limits. He's unbalanced--but in a good way.

My own experience has made me realize that this imbalance is no way to live the start-up life, and, in fact, it's detrimental to this kind of work. The only way I survive the dark periods is by constantly renewing myself and my perspective. Starting over is part of the process of starting up. That's something those in the entrepreneurial community should understand better than anyone else.