Is Unipolar Depression Genetic?

QUESTION:

Dear Dr. Heller,

I am very close to marrying a man who has unipolar depression in his family.  His grandfather, father and brother all suffer from unipolar depression.  My fiancée, however, does not have depression and I am not concerned that he will develop this disorder.  However, is it possible that my fiancée could have a dormant gene for depression and pass it along to any potential children that we produce?  Is there any research that discusses the genetics of unipolar depression?  Feel free to post this question to your web site, but could you please also reply to me directly.

Thank you.

ANSWER:

There are strong genetic links for most mental health diagnoses, including unipolar depression, but they are not absolute.

It's possible your fiancée will eventually get depressed as well, and the genetic link may or may not be passed on to your children. 

Many individuals without a family history of depression get depressed also, so there are absolutely no guarantees.