Assessing cognitive deficits in bipolar disorder: are self-reports valid?

Abstract

Patients with affective disorders frequently report problems with attention, concentration and memory, although little research has investigated subjective cognitive complaints relative to objective neuropsychological deficits. We compared subjective (self-rated) cognition and objective (clinician-rated) neuropsychological functioning in 37 DSM-IV bipolar outpatients. Subjects completed three standardized self-report inventories: the Cognitive Difficulties Scale (CDS), Cognitive Failures Questionnaire (CFQ), and Patient's Assessment of Own Functioning (PAOF). These were followed by a systematic neuropsychological test battery. More than 75% of our sample of bipolar patients displayed some cognitive deficits, most notably in the domains of verbal learning and memory. In general, patients' self-reports of impairment failed to reliably predict objective neuropsychological deficits. Mood ratings for mania and depression were not significantly correlated with any of the self-report inventories or the objective neuropsychological variables. The findings suggest that most bipolar patients demonstrate objective signs of cognitive impairment, but they are unable to report them accurately, at least using available self-report inventories. Such discrepancies could relate to impaired insight, efforts to conceal deficits, or to subthreshold affective symptoms.