eneral, the size of the amygdala appears to increase from childhood to adulthood in bipolar patients, starting out smaller than that of similarly-aged normal volunteers, but becoming larger than that of adult normal volunteers as the patients age into adulthood.
Lithium treatment increases gray matter volume in a variety of cortical areas and in the hippocampus in multiple studies. In contrast, treatment with valproate for 6 weeks appears to decrease hippocampal volume.
While the 4 major childhood-onset psychiatric illnesses we discussed this week (bipolar, unipolar, ADHD, and anxiety disorders) show long term difficulties into adulthood in the majority of instances, it appears that the most severely impacted are those with bipolar disorder. These data are also consistent with retrospective data from multiple cohorts of adults with bipolar disorder, which indicate that those whose illness began in childhood fared more poorly in adulthood than those with adult-onset illness. Thus, while there has been a modicum of treatment research in childhood depression and anxiety disorder and a plethora of treatment studies in ADHD, the dearth of treatment studies in children with bipolar disorder is all the more disconcerting.
Bipolar disorder is common, occurring in some 2 to 3% of children and adolescents, and carries a relatively grave prognosis into adulthood in the majority of instances, especially when it is inadequately treated. Virtually all of the investigators in the area of childhood-onset bipolar who presented at the AACAP meeting have pleaded for increased treatment research for bipolar disorder in children, and one can only hope that their message is soon heard.