Close relatives at risk…
According to findings from a study published in the January 17th issue of The Lancet, close relatives of people who have schizophrenia are at an increased risk of developing bipolar disorder. Conversely, close relatives of those with bipolar disorder possess an increased risk of developing schizophrenia. According to Paul Lichtenstein, Ph.D., of the Karolinska Institute, and colleagues, “schizophrenia and bipolar disorder share common genetic causes… and a considerable proportion of genetic variance is not in common with the other disorder, both for schizophrenia and bipolar disorder.” The researchers went on to say that “… some genes are probably associated with the risk for both disorders and some with the risk for only one disorder.” A notably higher risk was present among first blood relatives. The following is an excerpt of an article from Medpage Today that discusses the study in more depth:
Children and siblings of schizophrenic patients showed relative risks of 5.2 (95% CI 4.4 to 6.2) and 3.7 (95% CI 3.2 to 4.2), respectively, for having bipolar disorder themselves, reported Paul Lichtenstein, Ph.D., of the Karolinska Institute, and colleagues in the Jan. 17 issue of The Lancet.
For patients with bipolar disorder, their children and siblings had relative risks of 2.4 (95% CI 2.1 to 2.6) and 3.9 (95% CI 3.4 to 4.4), respectively, for developing schizophrenia, according to the study of some nine million Swedes.
Dr. Lichtenstein and colleagues found similar results among adopted-away children and siblings of schizophrenic and bipolar patients.
And among paternal half-siblings of patients — but not maternal half-siblings — there were significantly increased risks, although the magnitudes were attenuated.