These days, it’s becoming almost trendy for entrepreneurs to openly discuss their depression and other emotional afflictions. They’re getting hip to what some researchers have known for a while: the same obsessive drive that makes a good entrepreneur also has a dark side.

Yet Sheryl O’Loughlin, the co-founder of Plum Organics and the former chief executive of Clif Bar, says this dark side needs to be addressed even more openly.

In fact, it’s the subject of her new book, Killing It! An Entrepreneur’s Guide to Keeping Your Head Without Losing Your Heart. In it, O’Loughlin, who has taught entrepreneurship at Stanford University, tells the tale of her own struggle with personal demons. She hopes those tales and her advice about running a business will start a conversation with other entrepreneurs, and entrepreneurs-to-be.

O’Loughlin, who is now CEO of herbal drink company REBBL, sat down with Fortune to discuss her book.

The following interview has been edited for grammar and clarity. The book will be released on Dec. 6.

What was your motivation for writing the book?

O’Loughlin: I had these students who would come in with dollar signs in their eyes, and they were so excited to change the world with their companies. And that was incredible, but as an entrepreneur, there is the great light side, but also a dark side. When people hear about entrepreneurship in the media, it is all about this person who was a huge success [and] who made all this money. Students get the impression that is what it is all about. There is also drug abuse, divorce, depression, and suicide, and those are things that people don’t talk very much about. Entrepreneurs tend to talk about it after they’ve already been through it, and they will say, “I had a really hard ride.” I wanted people to understand this as they go into it, so it is not so scary.

 

Why do you suppose entrepreneurs have such tough time with depression?

O’Loughlin: As an entrepreneur, you are selling a vision in something that does not exist. You need investors to invest in it and employees to work for you when you can’t pay anything. Part of our job is being optimistic and positive and sunny. But it’s not only depression. We have a higher incidence of attention-deficit hyperactivity disorder and a higher propensity for drug abuse. The psychiatrist Michael Freeman says it’s a spectrum. On the one side, entrepreneurs are obsessive and dedicated and persistent, and that is the light side. That’s what makes them good entrepreneurs. But if I am also this person who is obsessive, it can result in depression.

So is this a business book or a self-help book?

O’Loughlin: There are a lot of gaps this book is filling. Most business books are: Here’s how you start a company. That’s in Killing It, too, and this is part of the story. The other part of the story is life and the human experience of life. That is also connected to the experience of the startup. I go into romance, marriage, children, [and] friendship. I talk about physical and emotional well-being. All of these are important.

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What is your story, about your demons?

O’Loughlin: At the same time I co-founded Plum Organics, my husband started a company that was the antithesis of [fast food]. It was an indoor place to bring your kids, to have creative activities, and healthy food. The day it opened — it had been freezing cold — it was beautiful and sunny, and it stayed that way for a couple of months. Two months into this, he came home and was a white as ghost saying we had run through all the cash. We had to close the doors, with a $20,000 a month lease still on us.

I had also started Plum. And I had a really, really rough investor who would tell me I was the greatest CEO one second, and the next, he would berate me. I would be in a board meeting telephonically, and he would text me that everything I was doing was wrong. I had the stress of starting my company, the stress of this investor, and the stress of my husband who then could not get out of bed for two months because of his depression. I was holding it all together, and over time, I developed an eating disorder.

What have you learned from all of this?

O’Loughlin: I have learned how to make the right choices. I know that every moment does not mean the company will fall apart, and I don’t tie [the company’s success or failure] to my self-worth anymore. That is what creates these demons. I also know how to make the right choice on investors. You need to go through entrepreneurship with a partner who supports you through the ups and down. We can be a tribe of entrepreneurs, who are connected and talk to each other in ways we are not talking now. Think of entrepreneurship in terms of your life as a whole.