Look for a job that will let you telecommute?

I don't know where you live or what the employment laws are in your jurisdiction, but for your own personal happiness and wellbeing it sounds like some kind of therapy may be your best solution in the long term. There are many good people out there who can help overcome phobias of all descriptions.

Thank you. I have seen a therapist that can verify this diagnosis. I will more seriously consider serious therapy for this problem. My question is more about what I should do in the meantime, as I cannot necessarily rely on a timeframe for cure, even if I started today.

Also I work in Omaha, Nebraska if that is relevant information.

Keshlam, unfortunately the nature of my work does not permit working remotely

Does your place of work have a disabled toilet? I'm not saying you are disabled, but if you could speak to your boss and be allowed to use it, these are generally single occupancy toilets so you may feel a lot more private than regular stalls.

Unless you want to invoke the nuclear option and threaten an ADA lawsuit, I don't see a quick solution here that doesn't reduce to fasting most of the day and trying to control when the need arises via diet and timing of meals. We demand dogs wait until we return from work; it should be possible to train an ape. This is an observation, not a recommendation, but you seem to be ruling out most alternatives to those bad choices.

Is there some floor in your building that no one uses / is "abandoned" ? Maybe the toilets there are still perfectly functional ;)

Another possible idea: do most of your coworkers go outside for lunch ? In that case, pretty much no one will be in the office during work hours, which gives you a good opportunity to do your thing.

For answer that is my of the practical workaround range, how extreme is the phobia in your case? It is clear than an empty stall is not enough for you. If the entire bathroom is empty except for you, would you be ok with people being on the same corridor (maybe hearing them through walls, etc.)? How about the same building?

What about discussing some sort of deal with your manager whereby you are allowed to lock the door of the entire bathroom while using it ? This has a higher chance of being allowed if there are multiple bathrooms on your floor/building so that other coworkers won't be affected.

"this is not a recognized mental health disorder at any company I have ever worked for" That is not for an employer to determine. I frankly find it difficult to believe that multiple employers would be so incredibly ignorant of the requirements of ADA when presented with an official diagnosis from a licensed medical expert. I assume you are applying to organisations covered by ADA?

You definitely want to talk to your employer's HR folks (or your manager if there is no HR) with a clear letter from your doctor.

To understand the problem from an employer point of view - Do you have some medical paper which prove than you have this phobia or did you diagnoses yourself that phobia?

You could also change your diet to minimize the number of times you need to go number 2 on the weekdays. (Don't eat indian or chili when you need to work the next day)

I've added a VTC as I don't think that this question can adequately be answered on SE (OP requires a dedicated support network for his condition). I also believe that much of the voting here is more about applauding a fist-fight than addressing the question...

I don't have this phobia but I still opt never to, um, "do this" anywhere but home. I can't say it's ever caused me a problem. You can't hold it for eight hours? Go in the morning? That sounds more like a medical issue.

@LightnessRacesinOrbit I don't see why it's difficult to get it onto a schedule. Lots of people manage it. Hell even I can manage it.

@Snowlockk: Indeed. Once every day or two or three should be enough and then you have all the flexibility in the world!! Some people don't have the same level of bowel control (I knew someone who had a form of IBS and had to go several times a day without much warning), and although the question seems to suggest that's the real problem here, the OP is focused on a fear of "fixing the problem" rather than the actual underlying medical condition (which is not explicitly mentioned). I find that a bit weird.

if you are guaranteed an empty bathroom would it be okay then? If so then you could ask is the company is willing to install a door lock on the bathroom itself in addition to the individual stalls. I've actual seen public bathrooms before that had this

I've worked in a place with door locks on the external bathroom doors and it was hell. Please don't even try to do that to your co-workers.

Rather, convince yourself that a bathroom stall satisfies your privacy criteria. After all you can lock the door of the stall, so you won't be interrupted and there won't be anybody joining you. Maybe you can use headphones and close your eyes, as suggested earlier.

And since you've shat your pants before, just go to the toilet and pull your pants down and just wait.

Now that I've thought about it a little, I'm starting to understand your employer.