Most entrepreneurs are well acquainted with stress, isolation, fatigue, and fear of failure. So too, it turns out, are those who suffer from depression. That's not entirely a coincidence; anecdotally, at least, the two are highly correlated. To be an entrepreneur is to take a dive into dark psychological waters, with the hope that you're a strong swimmer.

I've been thinking about this a lot lately, not just because I'm neck deep in startup life, but because my startup, Iodine, has recently released a product designed to help people manage their depression. Our mobile app, called Start, lets those taking an antidepressant decide if it's working for them. The idea is to create a feedback loop between the medication and the symptoms, giving people a path through the fog of their illness to a better place as fast as possible.

To describe depression--crassly--in business terms, it's a ripe opportunity for optimization. The market is inefficient. There's massive misalignment between the condition, the treatments, and the desired outcome. More than 30 million Americans over the age of 12 are taking antidepressants, making them the most prescribed class of medication for adults under 45. But, as many of these people discover, they don't always work. There's a 50 percent failure rate for antidepressants, 50 percent of people quit taking them, and only 10 percent receive adequate follow-up with their doctors. All that's good for our business plan, although it's miserable for the people suffering through ineffective treatment.

As we've studied depression, it's been eerie to see how similar its symptoms can be to the emotions common to entrepreneurship. The reme­dies are similar too. Like the clinically depressed, entrepreneurs are encouraged to find ways to cope with their circumstances. Getting exercise, talking honestly with peers--for many people with depression, these steps are as effective as pharmacology, and for many entrepreneurs, they make the difference between prosperity and misery.

Unfortunately, in the tumult of a startup, taking time away seems like a fantasy, and connecting with others seems like an indulgence. Yet I can say from experience, these "prescriptions" have been essential to my peace of mind. This summer, I made sure to ride my bicycle a lot, and I am fortunate to have several peers who've been generous with their time and counsel.

Thankfully, there's increasing attention being paid to clinical depression among entre­preneurs. Foundry Group VC and co-founder Brad Feld has written frankly for this magazine about his experience, encouraging others to step out of the shadows as well. And groups like Startups Anonymous help people share their stories and concerns. There's nothing more reassuring than a kind soul willing to admit that he or she hasn't figured it out either.

Unlike heart disease or diabetes, there's no blood test for depression. It's entirely symptomatic; what you feel inside--that brew of emotions that people often lack the vocabulary to describe--is the measure of the disease. And there's no magic pill for depression, no panacea that can cure it in one dose. Getting better is a process, one that takes time, trial, error--and hope. In the depths of despair, hope can be elusive, just as it can be when your business seems most vulnerable. Still, all entrepreneurs have two things in common. We believe that problems are meant to be solved, and we know that even dark days can't last longer than 24 hours. No one expects problems to disappear overnight. But each new dawn offers the chance for a new start.