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Neurocognitive profiles in bipolar I and bipolar II disorder: differences in pattern and magnitude of dysfunction
Author(s) -
Simonsen Carmen,
Sundet Kjetil,
Vaskinn Anja,
Birkenaes Astrid B,
Engh John A,
Hansen Charlotte Fredslund,
Jónsdóttir Halldóra,
Ringen Petter Andreas,
Opjordsmoen Stein,
Friis Svein,
Andreassen Ole A
Publication year - 2008
Publication title -
bipolar disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.285
H-Index - 129
eISSN - 1399-5618
pISSN - 1398-5647
DOI - 10.1111/j.1399-5618.2007.00492.x
Subject(s) - bipolar disorder , neurocognitive , bipolar ii disorder , psychology , bipolar i disorder , neuropsychology , cognition , psychiatry , clinical psychology , audiology , medicine , mania
Objectives: Studies on neurocognitive functioning in bipolar disorder, reporting deficits in memory, attention, and executive functioning, have primarily focused on bipolar I disorder. The aim of this study was to examine whether patients with bipolar I and bipolar II disorder have different neurocognitive profiles. Methods: Forty‐two patients with bipolar I disorder, 31 patients with bipolar II and 124 healthy controls, from a large ongoing study on psychotic disorders, were included. Neurocognitive function was measured with a comprehensive neuropsychological test battery. Results: The bipolar I group performed significantly poorer than the healthy control group and the bipolar II group on all measures of memory. Compared with the control group, the bipolar I group also had significantly reduced performance on most measures of attention and executive functioning, while the bipolar II group only had a significantly reduced performance on a subset of these measures. On average, 24% of the bipolar I group had clinically significant cognitive impairment (≤1.5 SD below the control group mean) across measures, compared with 13% of the bipolar II group. Conclusions: Patients with bipolar I and bipolar II disorder in this study have different neurocognitive profiles. Bipolar I patients have more widespread cognitive dysfunction both in pattern and magnitude, and a higher proportion has clinically significant cognitive impairments compared with patients with bipolar II. This may suggest neurobiological differences between the two bipolar subgroups.