Weight gain as a risk factor for progressive neurochemical abnormalities in first episode mania patients: a longitudinal magnetic resonance spectroscopy study

David J. Bond, Leonardo E. Silveira, Ivan J. Torres, Raymond W. Lam, Lakshmi N. Yatham

Research output: Contribution to journalArticlepeer-review

Abstract

Background. We previously reported that bipolar disorder (BD) patients with clinically significant weight gain (CSWG; ≽7% of baseline weight) in the 12 months after their first manic episode experienced greater limbic brain volume loss than patients without CSWG. It is unknown whether CSWG is also a risk factor for progressive neurochemical abnormalities. Methods. We investigated whether 12-month CSWG predicted greater 12-month decreases in hippocampal N-acetylaspartate (NAA) and greater increases in glutamate + glutamine (Glx) following a first manic episode. In BD patients (n = 58) and healthy comparator subjects (HS; n = 34), we measured baseline and 12-month hippocampal NAA and Glx using bilateral 3-Tesla single-voxel proton magnetic resonance spectroscopy. We used general linear models for repeated measures to investigate whether CSWG predicted neurochemical changes. Results. Thirty-three percent of patients and 18% of HS experienced CSWG. After correcting for multiple comparisons, CSWG in patients predicted a greater decrease in left hippocampal NAA (effect size = −0.52, p = 0.005). CSWG also predicted a greater decrease in left hippocampal NAA in HS with a similar effect size (−0.53). A model including patients and HS found an effect of CSWG on Δleft NAA (p = 0.007), but no diagnosis effect and no diagnosis × CSWG interaction, confirming that CSWG had similar effects in patients and HS. Conclusion. CSWG is a risk factor for decreasing hippocampal NAA in BD patients and HS. These results suggest that the well-known finding of reduced NAA in BD may result from higher body mass index in patients rather than BD diagnosis.

Original languageEnglish (US)
Pages (from-to)3783-3791
Number of pages9
JournalPsychological medicine
Volume52
Issue number16
DOIs
StatePublished - Dec 12 2022
Externally publishedYes

Keywords

  • Bipolar disorder
  • body mass index
  • glutamate
  • hippocampus
  • magnetic resonance spectroscopy
  • N-acetylaspartate

ASJC Scopus subject areas

  • Applied Psychology
  • Psychiatry and Mental health

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