Hippocampal volume not altered in youth with BD
MedWire News: Results from a Turkish study suggest that there are no significant differences in hippocampal volume between adolescents with and without bipolar disorder (BD).
However, Burak Baykara (Dokuz Eylul University, Izmir) and team found that mean hippocampal volume was larger in lithium-treated adolescents with BD than in untreated youth with the condition.
"The hippocampus is one of the key components of emotional regulatory networks in the brain," explain the researchers in the Journal of Affective Disorders.
But they add that "evidence about hippocampal changes in BD is quite limited and inconsistent, particularly for adolescent-onset BD."
To investigate further, the team studied 17 euthymic adolescents (seven boys), aged 13-19 years, with bipolar I disorder and 12 mentally healthy age-matched controls (five boys). Of the participants with BD, six had received treatment with lithium.
All of the participants underwent magnetic resonance imaging of the brain and had their hippocampal volumes recorded.
Analysis revealed no significant differences between BD patients and controls regarding mean right (3083.04 vs 3157.82 mm3) or left (2958.09 vs 2980.51 mm3) hippocampal volumes.
The researchers note that boys had significantly larger right hippocampal volumes than girls in both the BD and control groups, at 3139.20 versus 3043.73 mm3, and 3490.45 versus 3157.82 mm3, respectively.
They also found that, among adolescents with BD, boys and girls treated with lithium had significantly larger right hippocampal volumes than those who had not received lithium treatment. Lithium-treated BD patients also had larger left hippocampal volumes than untreated patients, but the difference was not significant.
Treatment with antipsychotics was not associated with hippocampal volume.
"The main findings of this study were that there was no significant difference between the right and left hippocampus volumes of patients with BD and the right and left hippocampus volumes of the control group," conclude Baykara and team.
They add: "Future, longitudinal follow-up studies need large enough sample sizes of both sexes and a sex-matched healthy comparison group to sort out developmental, sexual and medication influences on brain structures over time in BD."
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By Mark Cowen