PW01-15 - Neurocognitive Function in Clinically Stable Patients With Bipolar Disorder or Schizophrenia and Normal Controls

Abstract

Objectives

There is a substantial body of evidence that cognitive deficits in schizophrenia and bipolar disorder persist after the subsidence of active symptoms. The aim of the study was to assess and compare the cognitive functioning of patients with clinically stable schizophrenia and bipolar disorder.

Methods

Attention, memory, verbal learning ability, visuospatial ability, executive functions and social cognition were assessed in 21 patients with schizophrenia in remission, 23 euthymic bipolar-I patients, and 27 normal controls, using WAIS - Vocabulary, Block design, and Digit span, Stroop Test, Babcock Story Recall Test, Rey Auditory Verbal Learning Test (RAVLT), Trail Making Test (Trails A and B), Wisconsin Card Sorting Test (WCST), and Faux Pas Recognition Test. The three groups were matched for gender, age and education. One-way ANOVA with post hoc Bonferroni corrections was used for the between groups comparisons.

Results

Both bipolar disorder and schizophrenia patients were significantly impaired on tests of working memory, learning abilities, and executive functions compared to control subjects. Patients with schizophrenia performed significantly worse than patients with bipolar disorder on attention and verbal memory tasks, whereas the latter performed worse than normal controls on visuospatial ability tasks.

Table 1

Comparison of neuropsychological function

	Bipolar Disorder Mean (SD)	Schizophrenia Mean (SD)	Normal controls Mean (SD)	F	p	Post-hoc test (p)
WAIS - Vocabulary	10.1 (1.8)	10.2 (1.8)	12.0 (1.6)	6.06	.004	S < N (.015) B < N (.008)
WAIS - Block design	7.9 (2.5)	9.9 (3.6)	10.3 (2.7)	3.76	.032	B < N (.039)
Stroop - Word	84.3 (18.7)	82.3 (26.8)	97.7 (16.5)	4.03	.022	S < N (.038)
Stroop - Colour	59.5 (12.3)	56.8 (16.8)	72.0 (12.1)	8.74	.000	S < N (.001) B < N (.006)
Babcock - Delay recall	12.1 (3.9)	7.7 (3.3)	13.2 (3.3)	15.71	.000	S < N (.000) S < B (.000)
WCST - categories	2.4 (1.4)	2.5 (1.3)	3.1 (1.1)	2.49	.090	ns
WCST - perseverative errors	14.6 (13.1)	18.5 (16.4)	11.1 (8.2)	1.30	.280	ns
Trails B	164.1 (83.2)	170.2 (76.8)	86.7 (43.3)	11.68	.000	S > N (.000) B > N (.001)
Faux Pas - detection	38.6 (11.6)	40.1 (14.6)	46.2 (9.6)	2.64	.080	ns

Conclusions

Our results indicate that stable schizophrenia and euthymic bipolar disorder exhibit different but overlapping profiles of cognitive impairment.