Cortical thickness and surface area abnormalities in bipolar I and II disorders

Yoonmi Woo, Wooyoung Kang, Youbin Kang, Aram Kim, Kyu Man Han, Woo Suk Tae, Byung Joo Ham

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Objective Although bipolar II disorder (BD II) is not simply a mitigated form of bipolar I disorder (BD I), their neurobiological differences have not been elucidated. The present study aimed to explore cortical thickness (CT) and surface area (SA) in patients with BD I and BD II and healthy controls (HCs) to investigate the shared and unique neurobiological mechanisms of BD subtypes. Methods We enrolled 30 and 44 patients with BD I and BD II, respectively, and 100 HCs. We evaluated CT and SA using FreeSurfer and estimated differences in CT and SA among the three groups (BD I vs. BD II vs. HC). We adjusted for age, sex, educational level, and intracranial volume as confounding factors. Results We found widespread cortical thinning in the bilateral frontal, temporal, and occipital regions; cingulate gyrus; and insula in patients with BD. Alterations in SA, including increased SA of the pars triangularis and decreased SA of the insula, were noted in patients with BD. Overall, we found BD II patients demonstrated decreased SA in the right long insula compared to BD I patients. Conclusion Our results suggest that decreased SA in the right long insula is crucial for differentiating BD subtypes.

Original languageEnglish
Pages (from-to)850-863
Number of pages14
JournalPsychiatry Investigation
Issue number9
Publication statusPublished - 2021 Sept


  • Bipolar disorder
  • Bipolar subtype
  • Cortical thickness
  • Long insula
  • Surface area

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry


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