title: Meta-analytic review of neurocognition in bipolar II disorder.
abstract: OBJECTIVE
  The clinical distinction between bipolar II disorder (BD II) and bipolar I disorder (BD I) is not clear-cut. Cognitive functioning offers the potential to explore objective markers to help delineate this boundary. To examine this issue, we conducted a quantitative review of the cognitive profile of clinically stable patients with BD II in comparison with both patients with BD I and healthy controls.
  
  
  METHODS
  Meta-analytical methods were used to compare cognitive functioning of BD II disorder with both BD I disorder and healthy controls.
  
  
  RESULTS
  Individuals with BD II were less impaired than those with BD I on verbal memory. There were also small but significant difference in visual memory and semantic fluency. There were no significant differences in global cognition or in other cognitive domains. Patients with BD II performed poorer than controls in all cognitive domains.
  
  
  CONCLUSIONS
  Our findings suggest that with the exception of memory and semantic fluency, cognitive impairment in BD II is as severe as in BD I. Further studies are needed to investigate whether more severe deficits in BD I are related to neurotoxic effects of severe manic episodes on medial temporal structures or neurobiological differences from the onset of the illness.
authors.affiliation: Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton, Vic., Australia. emrebora@hotmail.com; boremre@gmail.com
authors.forename: E
authors.initials: E
authors.lastname: Bora
authors.forename: M
authors.initials: M
authors.lastname: Yücel
authors.forename: C
authors.initials: C
authors.lastname: Pantelis
authors.forename: M
authors.initials: M
authors.lastname: Berk
mesh_terms: D001288:Attention / Q000502:physiology; D001714:Bipolar Disorder / Q000503:physiopathology / Q000523:psychology*; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D008568:Memory / Q000502:physiology; D008570:Memory, Short-Term / Q000502:physiology; D009483:Neuropsychological Tests