What Causes Bipolar Disorder?

The answer to this question has never been entirely clear. But it is getting better.

Indeed, if you ask "what causes depression?", the answer is getting pretty good; and right now, it appears that this answer also applies to bipolar depression.

But that leaves mania. However, new research is beginning to shed more light on this. I just revised the essay on this subject on my website to reflect that new research. The bottom line: first, there is clearly a genetic component, but instead of one gene, there clearly are many that can be part of the problem, which is one reason why there are so many different versions of bipolar disorder. Secondly, at least one of the genes involved is part of the biological clock, the mechanism of which is now understood to a remarkable degree. Third, new research has revealed clues about the basic differences between the brains of people with bipolar disorder and those who do not have this illness.

If bipolar disorder can be so lethal sometimes, why is it still around? Why hasn't evolution selected it out long ago? Some speculations on this are offered at the end of the Web essay linked above.

Dr. Phelps