Manic behavior after longstanding depression

[alice]

My father, who is 88, has been exhibiting symptoms of mania for about a year.  We did not realize this at first because his internist thought it was early Alzheimer's and apparently his psychiatrist had not picked up on the symptoms since my father is very good at faking normality whenever other people are around, and always tries to make himself look in the best possible light to his psychiatrist, which is not very effective in getting at his problems.  

My mother finally went to the psychiatrist with him and spoke to the doctor alone and explained that my father had been flying into rages over nothing, staying up all night doing obsessive things like cutting all the covers off of paperback books, talks incessantly and doesn't want anyone to interrupt him, etc.  The psychiatrist decided it was manic behavior and agreed to put him in psychiatric care at the local hospital to try to find medications that may help him.  

My father has had major depression off and on for the past 20 years since he retired, but not mania.  The psychiatrist said sometimes people with long-standing depression do switch to mania.  I was wondering, is this true, and if so, what causes it?  He was on Ritalin and Celexa for his depression most recently and I wonder if that combination pushed him over the edge into mania.  He's off the Ritalin but was still taking a reduced dose of Celexa at the time he was diagnosed with the mania.  

I also wonder, when he was younger and I was living at home as a teenager and young adult, he had a great tendency to fly into irrational rages over minor transgressions even at that time.  Is it possible this was a symptom of hypomania that was never diagnosed at the time since it didn't bother him so he never sought help for it? He also experienced a lot of agitation when he was still working and was at various times on Milltown, Valium, Librium, prescribed by his internists at the time.  Would this indicate his manic side did exist prior to the clinical depression?  He was always very moody, could be up one minute and down the next.

Regarding the fear of Alzheimer's, is mania ever a symptom of Alzheimer's?  He did take that standard little test at a neurologist's office where the doctor asked him a lot of questions he had to answer, made him draw something, etc. and he passed that fairly well.  He also had a CT scan that was normal (he can't have an MRI due to a pacemaker).  We're still waiting for bloodwork results.

Any information you can provide on his situation would be helpful.  Thank you.

[Roger Gould, M.D.]

Mania is defintely a strong possibility with a history like this.