Never, never, NEVER disclose your bipolar to your employer unless you are asking for accommodations. It's none of their business, and your medical history is protected information. With few exceptions as noted above, nothing good comes from discussing mental illness at work, whether it's with other employees or management. I was burned very badly TWICE, and even if I were ever to go back to work (I'm on SSDI) I wouldn't share my MI with anyone if it's not absolutely necessary.