Cognitive function, treatment response to lithium, and social functioning in Japanese patients with bipolar disorder

• Published in: Bipolar disorders 2017-11, Vol.19 (7), p.552-562
• Main Authors: Saito, Satoshi, Fujii, Kumiko, Ozeki, Yuji, Ohmori, Kenichi, Honda, Gyo, Mori, Harunobu, Kato, Kazuko, Kuroda, Jinichi, Aoki, Akiko, Asahi, Haruhiko, Sato, Hayato, Shimoda, Kazutaka, Akiyama, Kazufumi
• Format: Article
• Language: English
• Subjects: Adult; Affect; Alda scale; Antimanic Agents - therapeutic use; BACS; Bipolar disorder; Bipolar Disorder - drug therapy; Bipolar Disorder - psychology; Case-Control Studies; Cognition; Cognition & reasoning; Cognitive ability; Cognitive Dysfunction - psychology; cognitive function; Emotional behavior; Female; Humans; Intelligence; Japan; Lithium; Lithium Compounds - therapeutic use; lithium responder; Male; Mental disorders; Middle Aged; Mood; Multiple regression analysis; Neuropsychological Tests; Patients; Regression Analysis; Schizophrenia; SFS; Social Adjustment; social function
• ISSN: 1398-5647; 1399-5618
• DOI: 10.1111/bdi.12521

Objectives Patients with bipolar disorder often suffer from cognitive impairment that significantly influences their functional outcome. However, it remains unknown whether lithium has a central role in cognition and functional outcome. We examined whether cognition and functional outcome were predicted by demographic and clinical variables, including the response to lithium, in lithium‐treated patients with bipolar disorder. Methods We evaluated 96 lithium‐treated euthymic patients with bipolar disorder and 196 age‐ and‐gender‐matched healthy controls, using the Brief Assessment of Cognition in Schizophrenia (BACS). The patients were also assessed using the Social Functioning Scale (SFS) and “The Retrospective Criteria of Long‐Term Treatment Response in Research Subjects with Bipolar Disorder” (Alda) scale, which was evaluated as either a continuous measure of the total scale or a dichotomous criterion. Results Multiple regression analysis revealed two key findings: first, that the premorbid intelligence quotient, age, and number of mood episodes were predictors of the BACS composite score; and, second, that the BACS composite score, negative symptoms, and continuous measure on the total Alda scale (but not its dichotomy) predicted the total SFS score. Structural equation modeling (SEM) was used to confirm these findings, and additionally revealed that the Alda scale was significantly associated with negative symptoms and also the number of mood episodes, regardless of how it was evaluated. Conclusions SEM delineated how demographic and clinical variables, cognitive performance, and response to lithium treatment were causally associated with, and converged on, social function. The putative role of the Alda scale for social function warrants further study.