Caudate choline levels reduced in medicated BD patients
MedWire News: Results from a US study suggest that medicated patients with bipolar disorder (BD) have reduced choline levels in the caudate nucleus of the basal ganglia, which is involved in mood expression and regulation.
Writing in the journal Psychiatry Research: Neuroimaging, Caleb Adler and colleagues from the University of Cincinnati in Ohio explain: "Several lines of evidence suggest that the neuropathophysiology of BD is marked by structural and functional abnormalities in the caudate."
To investigate ratios of certain biochemicals in the caudate of such patients, the team studied 25 adults with BD and nine mentally healthy controls. Of the BD patients, 14 were taking medications for their condition and 11 were unmedicated. Most of the medicated BD patients were taking atypical antipsychotics, the researchers note.
Magnetic resonance spectroscopy imaging was used to assess each participant for ratios of creatine/choline (Cr/Cho), choline/N-acetylacetate (Cho/NAA), and creatine/N-acetylacetate (Cr/NAA).
The researchers found that, overall, there were no significant differences in ratios of these biochemicals between bipolar disorder patients and controls, after accounting for age, gender, and gray/white matter ratio.
However, medicated BD patients had a significantly greater Cr/Cho ratio than controls, at 1.25 versus 1.08, with no significantly differences between unmedicated BD patients (Cr/Cho ratio 1.07) and controls.
Conversely, medicated BD patients had a nonsignificantly lower Cho/NAA ratio than controls, at 0.55 versus 0.61. The Cho/NAA ratio in unmedicated BD patients, at 0.62, was similar to that in controls.
Adler and team conclude: "Our findings suggest that while BD patients overall did not differ from healthy subjects, choline is decreased (based on elevated Cr/Cho and decreased Cho/NAA ratios) in the caudate of medicated bipolar patients."
They add that "this study suggests that medications, and particularly atypical antipsychotic medications, may decrease neuronal membrane turnover in bipolar patients. Although speculative, it is possible that these effects may be related to the long-term beneficial effects of effective mood stabilization."
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By Mark Cowen