Neurocognitive impairment evident in euthymic BD II patients
MedWire News: Euthymic patients with bipolar II disorder (BD II) show evidence of neurocognitive impairment, which may affect psychosocial functioning, say researchers.
"There is a growing body of evidence on neurocognitive impairment in euthymic bipolar patients, but this issue has been studied mostly in bipolar I disorder, [and] data on BD II are scant and discrepant," observe Eduard Vieta (University Clinic Hospital of Barcelona, Spain) and team.
To address this, the team studied 43 BD II patients, aged 18-65 years, and 42 mentally healthy controls who were matched for education level, age, and other demoghraphic variables.
All of the BD II patients were euthymic, with scores of 6 or less on both the Hamilton Depression Rating Scale (HDRS) and the Young Mania Rating Scale for at least 6 months before study enrolment.
The participants underwent a battery of neurocognitive tests to measure premorbid IQ, verbal learning and memory, executive functions, and attention. Psychosocial functioning was assessed using Social and Occupational Functioning Assessment Scale (SOFAS).
The researchers found that BD II patients performed significantly worse than controls on measures of attention, including the digits forward subtest of the Wechsler Adult Intelligence Scale (5.37 vs 6.31) and the Trail Making Test - part A (43.05 vs 31.48).
BD II patients also performed worse than controls on several measures of executive function including the Wisconsin Card Sorting Test categories and perseverative errors subtests (4.81 vs 5.57, 18.84 vs 8.98, respectively), the digits backwards subtest of the Wechsler Adult Intelligence Scale (4.19 vs 4.79), and the Trail Making Test (TMT) part B (105.16 vs 78.76).
In addition, BD II patients had poorer scores than controls on most tests of learning and verbal memory.
The researchers note in the journal Acta Psychiatrica Scandinavica the presence of subthreshold depressive symptoms and scores on the TMT part B best predicted psychosocial functioning. Indeed, HDRS scores (mild depressive symptoms) explained 30.4% and the TMT part B explained 15.9% of the variance of psychosocial functioning as measured through the SOFAS.
Vieta and team conclude: "This report provides further evidence that euthymic BD-II patients present cognitive impairment, which may impact psychosocial functioning."
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By Mark Cowen