We found bipolar illness and traumatic brain injury to
be unassociated within the bipolar disorder pedigrees, but
only pedigree of origin was associated with the risk for bipolar
illness in controlled analyses. Although subjects
with major depression from the schizophrenia pedigrees
were twice as likely to have traumatic brain injury as those
from the affective disorder pedigrees, this excess was similar
to the overall surplus of traumatic brain injury in the
schizophrenia families.