title: Neurocognitive features in subgroups of bipolar disorder.
abstract: OBJECTIVE
  To examine which subgroups of DSM-IV bipolar disorder (BD) [BD type I (BD-I) or BD type II (BD-II), and subgroups based on history of psychosis, presenting polarity, and age at onset] differentiate best regarding neurocognitive measures.
  
  
  METHODS
  A total of 199 patients with BD were characterized by clinical and neurocognitive features. The distribution of subgroups in this sample was: BD-I, 64% and BD-II, 36%; 60% had a history of psychosis; 57% had depression as the presenting polarity; 61% had an early onset of BD, 25% had a mid onset, and 14% had a late onset. We used multivariate regression analyses to assess relationships between neurocognitive variables and clinical subgroups.
  
  
  RESULTS
  Both BD-I diagnosis and elevated presenting polarity were related to impairments in verbal memory, with elevated presenting polarity explaining more of the variance in this cognitive domain (22.5%). History of psychosis and BD-I diagnosis were both related to impairment in semantic fluency, with history of psychosis explaining more of the variance (11.6%).
  
  
  CONCLUSIONS
  Poor performance in verbal memory appears to be associated with an elevated presenting polarity, and poor performance in semantic fluency appears to be associated with a lifetime history of psychosis.
authors.affiliation: KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Ullevaal Hospital, Oslo, Norway.
authors.forename: Sofie Ragnhild
authors.initials: SR
authors.lastname: Aminoff
authors.forename: Tone
authors.initials: T
authors.lastname: Hellvin
authors.forename: Trine Vik
authors.initials: TV
authors.lastname: Lagerberg
authors.forename: Akiah Ottesen
authors.initials: AO
authors.lastname: Berg
authors.forename: Ole A
authors.initials: OA
authors.lastname: Andreassen
authors.forename: Ingrid
authors.initials: I
authors.lastname: Melle
mesh_terms: D017668:Age of Onset; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000145:classification* / Q000150:complications*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D006801:Humans; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology*; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000209:etiology; D012044:Regression Analysis; D014706:Verbal Learning / Q000502:physiology