Q. Four generations of family, possibly five, have a history that includes severe mental illness. This is not a matter of nurture as we were all raised separately. How common is this? I have chosen to not have children due to this legacy.
Answer By: Eric J. Nestler, M.D., Ph.D.
Icahn School of Medicine at Mount Sinai
Unfortunately, this is not uncommon, since all forms of severe mental illness are highly heritable, in particular, schizophrenia and bipolar disorder. The chances of this type of scenario likely vary a lot from family to family, since the heritability and specific genes that comprise that heritability vary.