I think the results of such disclosure varies from employer to employer. It can be detrimental, but then again it can be quite helpful. I ended up disclosing to my last employer when they threatened to fire me for manic behavior. They were going to give me a chance to fix the behavior. At that time, I had not been accepting treatment, and frankly, had not yet really accepted my diagnosis. I had been formally diagnosed the year before.

The day after the threat, I was hospitalized. After the hospitalization, I was in a PHP then IOP for a full six months. My employer held my job that whole time. When I returned to work, I was given an accommodation. I had several more hospitalizations. They welcomed me back and at one point I even was allowed to work from home 3 out of 5 days.

Eventually it became obvious that I was too disabled to work, so I applied for SSDI. It was only at that stage that they terminated my employment (not fired). Three and a half years after my first hospitalization. So, I can't say anything bad about my past employer.