I was in MS and was denied for 3 years for a physical disability. They want you to A) just go away or B) die.
However, I am now in FL and my neighbor applied for SSI due to her Bipolar and was approved within 3 months. Astounding. Perhaps it is the state you live in.
Everyone I know got denied for ssi the first time they applied. I have a major depression and borderline personality diagnosis and I am on SSI. If you have a social worker they should be helping you to apply. I know there are some law companies that specialize in helping people get SSI but I don't know their names. If you call the SSI office expect to stay on hold for a long time. I have been on hold for almost an hour in the past. If you are in a smaller city try your local office, they are usually a lot more willing to explain things. Good luck!