Five-year prospective outcome of psychopathology in the adolescent offspring of bipolar parents.
Hillegers MH, Reichart CG, Wals M, Verhulst FC, Ormel J and Nolen WA;
Commented by , 22 Aug 2005
Background
Prior reviews of studies of offspring of bipolar parents have found that approximately 5% of the offspring are diagnosed with a bipolar disorder (ref. 1), while recent reviews have concluded that the prevalence of mood disorders range from 5 to 67% in child and adolescent offspring (ref. 2).
Many of these studies may present biased findings as most studies include small samples of ill parents mostly below 60 and as these findings most often are based on cross-sectional studies.
Method
The present paper presents findings from the third investigation of 129 offspring of 86 patients with bipolar disorder who were recruited through a Dutch patient association and from psychiatric hospitals.
The mean time from first investigation was nearly 5 years and the mean age of the offspring was 20.8 years. Lifetime DSM-IV diagnoses were obtained from SCID interviews.
Results
The lifetime prevalence of bipolar disorder was 10% increasing from 3 and 6% in the first and second investigation. The lifetime prevalence of mood disorders was 40%, and of psychopathology in general 59%.
All 13 patients with a bipolar disorder except one debuted with a depression at a mean of 5 years prior to their first (hypo)manic episode. In five of these subjects the first episode was a major depression.
Professor Kessing's comments
This is a well-designed and rigorously performed study showing that at the age of 16-25 years 10% of offspring of parents with bipolar disorder will have developed a bipolar disorder and 40% a mood disorder of any kind.
As pointed out by the authors these figures will most probably increase further at future investigations of the sample. Such high figures are in accordance with findings from recent studies but contrast the lower figures found in earlier cross-sectional studies.
The findings have two main implications. From a methodological point of view, the findings put emphasis on the importance of conducting longitudinal studies when investigating offspring of psychiatric patients.
From a clinical point of view, the findings put emphasis on the genetic loading of bipolar disorder in accordance with the finding that the genetic effect in bipolar disorder is among the highest in psychiatric illness.
Such high prevalence of bipolar disorder and mood disorder in general also points to the intriguing possibility of primary prophylaxis of mood disorder as the offspring of bipolar patients may be a target for intervention of psychological or social origin as well as even medical prophylaxis, eventually.
The prophylaxis may especially focus on offspring to parents with bipolar disorder who present with mild depressive episodes.
References
1. Lapalme M, Hodgins S, LaRoche C. Children of parents with bipolar disorder: a metaanalysis of risk for mental disorders. Can J Psychiatry 1997; 42 (6); 623-631
2. Geller B, Tillman R, Craney JL, Bolhofner K. Four-year prospective outcome and natural history of mania in children with a prepubertal and early adolescent bipolar disorder phenotype. Arch Gen Psychiatry 2004; 61 (5); 459-467