Earlier Age of Onset of Bipolar Illness in the US Compared to Europe
As we have previously reported in the BNN, the Bipolar Collaborative Network (including this editor Robert M. Post) found that patients from 4 sites in the United States had significantly earlier ages of onset of their bipolar illness compared to 3 sites in the Netherlands and Germany). These findings have been replicated by Frank Bellivier et al., who used a broader sample of European participants.
Bellivier’s research group studied two large samples of bipolar I patients from the US (n= 2275) and from 14 countries in Europe (n= 3616). The researchers found 3 different distributions of age of onset, and patients from the US had a greater representation in the early age of onset subgroup. Sixty-three percent of the sample from the US fell into the early-onset group versus 25% of those from Europe. The mean age of onset of the early-onset subgroup was significantly lower in the US sample (14.5 +/- 4.9 years) than in the European sample (19 +/- 2.7 years).
Editor’s Note: It is time that we took these geographical differences in the frequency of early age of onset of bipolar disorder seriously. While some controversy has surrounded the diagnosis of bipolar illness in children, it becomes increasingly important to recognize that this bona fide, well-diagnosed illness is more common in children from the US than from many other countries. Affected children should have careful clinical evaluation and, if the diagnosis warrants, definitive treatment. This should include both psychoeducational approaches; focused psychotherapies, including the family-focused therapy pioneered by Dave Miklowitz; and psychopharmacological intervention. When this kind of combined treatment is implemented, young patients who are treated with lithium, another mood stabilizer, or an atypical antipsychotic do much better than those who do not receive these consensus-based treatments.
Treatment algorithms for children of different ages with bipolar disorder are still being developed. However, it appears that in young and very young children, the atypical antipsychotics are often more effective than lithium or valproate monotherapy, as suggested in recent large randomized clinical trials. Initiating appropriate treatment is extremely important, since the duration of the untreated interval (that is, the time from illness onset to first treatment) is directly related to worse outcomes in adulthood. The longer the duration of untreated illness, the greater the severity of depression, the longer the duration of depression, and the greater the number of episodes an adult experiences.
As might be expected from the earlier age of onset of bipolar disorder, US patients also have a higher incidence of the major vulnerability factors for early onset—more genetic vulnerability (parents with bipolar disorder), more childhood stressors, and more stressors in the year prior to illness onset. Patients from the US also had a variety of other poor prognosis factors, including a higher degree of anxiety comorbidity, alcohol and substance abuse problems, a higher incidence of having more than 20 episodes over their lifetime, and a higher incidence of rapid cycling. All of these characteristics combine to produce worse outcomes in adult patients from the US compared to those from Europe. Earlier and more judicious treatment of the illness in the United States is needed to help ward off this more pernicious course of bipolar illness.
