Comparing mania and depression

Similar findings have been reported from work on comparative cognitive performance in mania and depression. Bulbena & Berrios (1993) assessed performance of patients during acute episodes of major depression and mania using tests of attention, memory, visuospatial function and choice reaction time. Relative to controls, patients were impaired on most cognitive measures, but no differences between mania and depression were found. Moreover, Goldberg et al (1993) found that in bipolar disorder, patients in manic and depressed episodes did not differ on the Wechsler Adult Intelligence Scale — Revised (WAIS—R), WCST, or on neuropsychological tests of reading, line orientation and facial recognition.

While direct statistical comparison between patients with mania and depression is clearly the best approach in searching for distinct neuropsychological profiles, indirect comparison between patient groups who have been assessed using standardised neuropsychological tasks can also be informative. In a study by Murphy et al (1999), patients in the manic phase of bipolar illness were given tests of memory and executive function taken from the Cambridge Neuropsychological Test Automated Battery (CANTAB, CeNes Plc, Cambridge, UK). These tests are reliable and valid (Robbins et al, 1994, 1998), and had been previously administered as part of a much larger test battery to a sample of patients with major depressive disorder (Elliott et al, 1996). Patients with mania demonstrated substantial impairments on tests of pattern and spatial recognition memory, and delayed visual recognition. This pattern of impairment was strikingly similar to that previously observed in patients with depression (Table 1). Executive function, as assessed by the computerised one-touch Tower of London test of planning ability, was also similarly impaired in the two patient groups (Fig. 1).

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