Neurocognitive dysfunction and psychosocial outcome in patients with bipolar I disorder at 15-year follow-up

Abstract

Objective: Despite increasing interest in cognitive dysfunction in bipolar disorder, little is known about its impact on functional outcome relative to affective symptoms.

Method: A total of 33 bipolar I subjects were evaluated at index hospitalization and prospectively followed up 15 years later. Affective symptoms, cognition, global functioning, work, and social adjustment were assessed at follow-up and analyzed by linear regression.

Results: Global functional impairment was significantly associated with poor performance on a cognitive measure of processing speed (WAIS Digit Symbol). Digit symbol performance also was the sole significant predictor of social functioning. Neither symptom severity nor course of illness features significantly contributed to global and social functioning. In contrast, verbal learning deficits, recent depression, and lifetime hospitalizations all were independently associated with work disability.

Conclusion: Processing speed is robustly associated with social and global functioning in bipolar disorder. Poor work functioning is significantly related to subsyndromal depression, course of illness, and verbal learning deficits. Cognitive and mood symptoms warrant consideration as independent determinants of functioning in patients with bipolar disorder many years after an index manic episode.

Fig. 1

Bipolar patients neurocognitive performance vs. normative data: The data depicted represent neurocognitive performance of our patient sample in comparison with published normative data. The X-axis labels the neurocognitive measures administered, and the Y-axis is a Z-score scale, with a mean of zero and standard deviation of one. Abbreviations include Info (Wechsler Adult Intelligence Scale-R WAIS-R Information); Digit Sym (WAIS-R Digit Symbol); Fluency (Controlled Oral Word Test COWAT letter fluency FAS); Trail A (trail making test Part A); Trail B (trail making test Part B); CVLT 1–5 (California Verbal Learning Test Total Trials 1–5); WCST Persev (Wisconsin Card Sorting Test Perseverative Errors).