Processing speed linked to functioning in bipolar patients
MedWire News: Processing speed is associated with social and global functioning, and work functioning is linked to depression, illness course, and verbal learning in patients with bipolar disorder, research shows.
Writing in the journal Acta Psychiatrica Scandinavica, Joseph Goldberg (Mount Sinai School of Medicine, New York, USA) and team explain: "Despite increasing interest in cognitive dysfunction in bipolar disorder, little is known about its impact on functional outcome relative to affective symptoms."
To investigate, the researchers studied 33 patients with bipolar I disorder who were followed-up for 15 years after diagnosis.
All the patients were evaluated at baseline and underwent extensive neurocognitive tests at follow-up, including evaluations of verbal learning and memory, processing speed, verbal fluency, executive function, and general knowledge.
The researchers found that global functional impairments were significantly associated with poor performance on tests of processing speed, as measured using the Wechsler Adult Intelligence Scale (WAIS)-Digit Symbol test.
Furthermore, poor performance on the WAIS-Digit Symbol test was significantly associated with poor social functioning.
Verbal learning deficits, recent depression, and lifetime number of hospitalizations were all positively associated with work disability.
However, global and social functioning was not associated with symptom severity or course of illness.
Goldberg and team conclude: "The present findings highlight the fundamental nature of cognitive impairment as a separable dimension from residual or persistent depressive features in a substantial number of individuals with bipolar disorder at follow-up, and point to the need for assessing cognitive status as well as affective symptoms in future studies of functional outcome."
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By Mark Cowen