Ya I totally get that, you mentioned a long psychotic episode. I have asked on here before about this and I did not find much info. In fact I have not been able to find much info anywhere, not that I have searched extensively but I have searched. I did find the following in the wikipedia.

"Tertiary brain cortex collects the interpretations from the secondary cortexes and creates a coherent world view of it. A study investigating structural changes in the brains of people with psychosis showed there was significant grey matter reduction in the right medial temporal, lateral temporal, and inferior frontal gyrus, and in the cingulate cortex bilaterally of people before and after they became psychotic. Findings such as these have led to debate about whether psychosis itself causes excitotoxic brain damage and whether potentially damaging changes to the brain are related to the length of psychotic episode. Recent research has suggested that this is not the case although further investigation is still ongoing."

So still no answer in itself, but it is interesting.

http://www.sciencedaily.com/releases...0310175130.htm

There is a lot of research into cognitive deficiencies and schizophrenia, which I think is interesting, when you are looking at the psychotic episodes in Bipolar particularly lengthy ones.