Parental bipolar history common in US bipolar patients

By Ingrid Grasmo, medwireNews Reporter

Research findings suggest that patients with bipolar disorder who reside in the United States have a higher parental incidence of bipolar disorder and depression than those who live in Europe.

The study, published in Acta Psychiatrica Scandinavica, also showed that a parental history of bipolar disorder or depression was significantly associated with an earlier age of onset of bipolar disorder in the US compared with in Germany and the Netherlands.

"Greater attention to early recognition, diagnosis, and treatment of childhood onset bipolar disorder especially in the United States is indicated," say Robert Post (Bipolar Collaborative Network, Bethesda, Maryland) and co-authors.

They add: “Attention to the parental loading of unilineal bipolar disorder and bilineal mood disorder may facilitate evaluation and potential psychotherapeutic and pharmacological intervention in those at highest risk.”

Analysis of self-reports from 525 patients with bipolar disorder from 1995–2002 revealed that US patients had a significantly higher proportion of parents with a history of bipolar or unipolar depression compared with European patients.

Specifically, 21% of US patients had one parent with a history of bipolar disorder, compared with 10% of European patients, while in 15% versus 4% of patients both parents had bipolar or unipolar depression.

A parental history of bipolar disorder or depression was significantly associated with an earlier illness onset, an increased history of physical or sexual abuse, anxiety disorder, rapid cycling, experiencing 20 or more mood episodes, and a higher number of total poor prognostic factors.

Findings from multinominal regression analyses showed that if patients had one parent with bipolar disorder or two parents with a mood disorder, they were a significant 54% and 69% less likely to be from Europe than the US and were significantly more likely to have an early age of onset.

The researchers caution that these preliminary findings require replication, not only in other patient samples but also using more controlled epidemiologic methods.

“If the findings are replicated, their potential sociological and neurological mechanisms as well as their clinical and treatment implications deserve further exploration and disentanglement,” they conclude.

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