I have bipolar disorder, too. I applied online and was approved in three months.

It's important to list doctors, hospitals, any treatment you received. The government will obtain the records to examine your application.

My psychiatrist and therapist strongly felt I was no longer able to work and that was due to bipolar making me disabled. I know they were contacted and they submitted their opinion as to whether I was disabled ...

I don't know details but it seems very important to be undergoing regular treatment for your illness(es), as well as your treatment team believing you are disabled under SSDI guidelines.