Childhood bipolar I disorder same diathesis as adult bipolar I disorder


11 October 2006

Researchers have confirmed that prepubertal and early-adolescent bipolar I disorder phenotype (PEA–BP-I) and adult bipolar I disorder represent the same condition.

Barbara Geller and team from Washington University in St Louis Missouri, USA, found that familiality was seven to eight times greater in child versus adult bipolar I disorder.

"A key question is whether children with PEA–BP-1 have the same illness as their adult counterparts," the researchers note in the Archives of General Psychiatry.

"This question arises because of the greater severity, longer current episode, preponderance of mania, and high rates of ultradian rapid cycling and comorbid attention deficit/hyperactivity disorder (ADHD) in child mania in prospective and retrospective studies."

To try and end this debate, Geller and co-workers examined the morbid risk of bipolar I in first-degree relatives of children and adolescents aged between 7 and 16 years who had PEA–BP-1 (n=95), ADHD (n=47), or no mental health condition (n=77). In all, there were 690 relatives who were 6 years or older than the probands.

The morbid risk of bipolar I was higher for relatives of PEA–BP-1 individuals than for those of children with ADHD or mentally healthy controls, at 34.0% versus 13.8% and 4.7%, respectively.

Moreover, the morbid risk of bipolar I disorder in first-degree relatives was higher if relatives had ADHD, oppositional defiant disorder, conduct disorder, or antisocial personality disorder.

Indeed, the prevalences of both bipolar I disorder without ADHD and with ADHD were both significantly greater in the relatives of PEA–BP-1 than those of controls, at 11.3% and 16.9% versus 1.9%, respectively.

Relatives also tended to develop bipolar I disorder at a younger age if they had ADHD, and there was evidence of anticipation, defined as an earlier age at onset in more recent generations.

"Greater familial aggregation in child versus adult bipolar I disorder, in addition to greater severity and early age at onset in PEA–BP-1 is consistent with the Childs and Scriver paradigm for illness across the medical spectrum," the researchers note.

This means that PEA–BP-1 and adult bipolar I disorder are the same diathesis with developmental phenotypic differences, with age at onset occurring earlier for genetic and environmental reasons, they explain.

This is confirmed in the current study by the finding that bipolar I disorder and bipolar I disorder with ADHD occurred in the same families.



Source: Arch Gen Psychiatry 2006; 63: 1130–1138