Objective: Few studies have examined the neurochemical abnormalities that might be associated with pediatric bipolar disorder. The aim of this study was to use magnetic resonance spectroscopy to evaluate several brain regions implicated in bipolar disorder in children with a mood disorder and a familial risk for bipolar disorder. We hypothesized that these children would exhibit neurochemical differences compared with healthy children of parents without a psychiatric disorder. Specifically, decreased N-acetylaspartate (NAA) and creatine and phosphocreatine (Cr) of the prefrontal cortex and cerebellar vermis would reflect impairments in neuronal function and cellular metabolism, and elevated myo-inositol (mI) would reflect impaired phosphoinositide metabolism, potentially representing early markers of neurophysiologic changes that might underlie the development of bipolar disorder.
Methods: Children with a mood disorder and at least one parent with bipolar disorder (n = 9) and healthy children (n = 10) group matched for age (8-12 years), race, sex, education, and Tanner stage were evaluated using the Washington University in St. Louis Kiddie Schedule for Affective Disorders and Schizophrenia. Proton magnetic resonance spectroscopy was acquired using 8-cc volumes within the frontal cortex, frontal white matter, and the cerebellar vermis. Metabolite ratios (NAA/Cr, cholines (Cho)/Cr, mI/Cr, NAA/Cho, NAA/mI, and Cho/mI) and concentrations (NAA, Cr, Cho, and mI) were calculated and compared between groups.
Results: The trend in concentration levels of NAA and Cr was approximately 8% lower for children with a mood disorder than healthy children within the cerebellar vermis. The frontal cortex in children with a mood disorder revealed elevated mI concentration levels, approximately 16% increased, compared with healthy children.
Conclusions: Similar to findings in adults with bipolar disorders, neurochemical abnormalities within the frontal cortex and the cerebellar vermis were present in this preliminary comparison of children with a mood disorder and a familial risk for bipolar disorder. Larger sample sizes are needed to replicate these findings.