Fronto-limbic brain abnormalities in juvenile onset bipolar disorder

Background: Advances in brain imaging techniques and cognitive neuropsychology have brought new possibilities for the in vivo study of the pathophysiology of neuropsychiatric disorders, including bipolar disorder (BD). Recently, such studies have been extended to the pediatric age range. Here we review the neuroimaging and neuropsychological studies conducted in BD children and adolescents. Methods: A review of the peer-reviewed published literature was conducted in Medline for the period of 1966 to April 2005. Results: Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) studies suggest abnormalities in fronto-limbic structures in pediatric BD patients, similar to those found in adults. A notable exception in pediatric BD patients is smaller amygdala volumes compared to healthy controls, contrary to what has been reported in most adult studies. Conclusions: Further research evaluating children and adolescents is needed to study the normal neurodevelopmental process and to answer how and when the illness processes that result in bipolar disorder exert their effects on the developing brain.