Family Risk of Bipolar 1 and 2 Disorders and Schizophrenia

Peter ForsterDiagnosis, Psychobiology Leave a Comment

Interesting study out of Taiwan that uses their fairly comprehensive population based data set to look at the relative risk of having different disorders in a family where one parent either has bipolar one or bipolar two disorder. I found this study interesting in that it suggests that bipolar one has a higher genetic loading for any kind of bipolar disorder (but especially bipolar 1) or a psychotic disorder in children whereas bipolar 2 is perhaps more non specific with an equal increased risk of bipolar one and bipolar 2 and no particularly high risk of schizophrenia.

Bipolar 1 families are much more likely to have bipolar 1 children, and about equally likely to have bipolar 2 children as to have schizophrenic children. Bipolar 2 families are equally likely to have bipolar 1 as bipolar 2 children and have a somewhat smaller increased risk of having children with major depression, OCD or ADHD (all at roughly the same relative risk).

This aligns with the notion that bipolar 1 is a more genetically determined mood disorder that has some overlap with the genetics of psychosis, whereas bipolar 2 is a more heterogenous disorder with overlap with bipolar 1 and 2, major depression, ADHD, OCD and anxiety.