What are your thoughts on Bipolar Disorders?
I have had friends and family who have been diagnosed bipolar, and a couple of the friends committed suicide.
I have had fairly manic episodes in my life, with times when the elation depression cycles were down to 20 minutes, and I am much calmer now (perhaps partially due to cashew nuts as a constant in the diet).
There certainly seems to be a strong genetic tendency toward bipolar, and as OM said, diet and mental state can each also put large contributions towards anything, and bipolar is no exception. And for some people the mental work is easier than for others.
Like most things in life, it is complex, no simple or consistent answers.