Over the years, I have discovered a topic that is very close to being a third rail among entrepreneurs in open forums. Very few will admit to it or even talk about it. But it is a very different story in private.

Discreetly, a surprising number of entrepreneurs, even very successful ones, confess that they clearly remember their bouts with it. For many, it appears regularly and even becomes an undercurrent of their life. For others it is an intermittent visitor, unpredictable, and unwelcome.

It is entrepreneurial terror, an all-encompassing dread that comes from nowhere and throws its coils around you like a python ready to feed. The coils grow tighter and tighter suffocating you and sucking the life force out of you. You look into the abyss and there is nothing to prevent you from toppling headfirst into it. You scream soundlessly and no one can hear.

Many describe it as the most frightening experience they have ever had.

Take this fictional story about Dave, a composite I created based on conversations with dozens of entrepreneurs:

The day began to go wrong long before Dave reached his office. He had finished working out on the treadmill and was grabbing his car keys when Joe called on his cell. His three year old was running a fever so he would not be coming in to work. Joe was his tech-guy, the only person who understood the new CRM package on which they had just spent a king's ransom. More, their new product launch--a 'make or break' for the company--was scheduled for later in the week and 2 million emails needed to go out smoothly.

Joe was apologetic. He promised to work from home and fix the bugs they had identified but Dave felt queasy.

His night receptionist handed him a message when he reached his office. Bob wanted to speak with him immediately. Bob was his lead investor, the guy who had found the other investors for him and promised him that he would back him till the end of the quarter when the results of the product launch were in. If all went well, the company would be able to self-finance for the rest of the year.

Bob, like Joe, was apologetic. He had tried his best but his partners were not very happy with the results so far. He could no longer guarantee that he would be there for Dave as promised. But what about the new product launch, Dave sputtered.

Bob was sympathetic but he was not reassuring. He would do his best but Dave had better start working on a plan B.

Dave got another call from Joe that evening. His child was still sick. He was sorry but the strain was too great. He was quitting, effective immediately.

It took a long time for Dave to fall asleep and he woke up in a cold sweat at 3AM. Steel bands were clamped around his chest and he could barely breathe. Fear, stark uncontrollable fear, permeated every cell and flowed out through every pore. He felt his body stirring, moving involuntarily.

"What's up dear?" his wife mumbled sleepily.

"Nothing," he lied.

He found that he had curled up in the fetal position.

Again, Dave is fictional, but the entrepreneurial terror his story describes is all too real. It is a primordial feeling that overrides intellect and takes you over completely. It is generally triggered by an adverse event but can sometimes come from nowhere and as part of regular mood swings. It also differs from that of any individual who has faced a setback because the depth is greater--the very self seems about to disappear--and because entrepreneurs feel compelled to keep it to themselves like a deep, dark secret. Indeed, the recent Inc. article The Psychological Price of Entrepreneurship found researchers report many entrepreneurs share innate character traits that make them more vulnerable to strong emotional states.

Entrepreneurial terror is debilitating in the extreme.

And most entrepreneurs have experienced some variation of this at some point in their careers. And quite a few have had multiple bouts with it.

In my next column I write about how to deal with this monster.