Estimating Cognitive Impairment in Bipolar Disorder: Should We Account for Premorbid IQ?

IF 4.7 2区医学 Q1 PSYCHIATRY

Acta Psychiatrica Scandinavica Pub Date : 2026-04-05 Epub Date: 2025-06-18 DOI:10.1111/acps.70000

Dimosthenis Tsapekos, Michail Kalfas, Rebecca Strawbridge, Samuel Swidzinski, Katherine E. Burdick, Allan H. Young

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Abstract

Introduction

Cognitive impairment estimations traditionally rely on the deviation of current cognitive performance from population norms (normative approach). Since bipolar disorder (BD) has been associated with above-average premorbid cognitive functioning in some studies, this approach might underestimate the extent of cognitive impairment in a proportion of patients. We examined whether intraindividual deviation of cognitive performance from premorbid estimates (idiographic approach) would more accurately estimate impairment in BD and assessed the functional relevance of this approach.

Methods

This study pooled euthymic patients with BD (N = 257) taking part in two cognitive remediation trials with comparable eligibility criteria and measures. All participants underwent a baseline assessment including measures of current cognition, premorbid IQ, psychosocial functioning and mood symptom severity. We estimated and compared the prevalence of normative versus idiographic impairment and examined the association of the idiographic approach with functioning.

Results

According to normative standards, 13%–31% of our euthymic sample was classified as cognitively impaired depending on the adopted cut-off. After accounting for premorbid IQ, idiographic impairment rates increased to 37%–64%. The difference between the two approaches was significant for each cut-off considered (0.5 and 1 SD). Idiographic cognitive impairment was significantly associated with psychosocial functioning, even after controlling for residual mood symptoms and demographic/clinical variables and functional impairment classification.

Conclusion

Common practices for characterising cognitive impairment using a normative approach may underestimate the extent of impairment for a substantial proportion of euthymic patients with BD. Considering idiographic impairment provides an alternative, functionally relevant approach for cognition trials and clinical practice.

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估计双相情感障碍的认知障碍：我们应该考虑发病前的智商吗？

传统上，认知障碍估计依赖于当前认知表现与总体规范的偏差（规范方法）。由于双相情感障碍（BD）在一些研究中与高于平均水平的发病前认知功能相关，这种方法可能低估了一部分患者认知功能障碍的程度。我们研究了个体内认知表现偏离病前估计（具体方法）是否能更准确地估计双相障碍，并评估了这种方法的功能相关性。方法：本研究收集了257例健康BD患者，他们参加了两项具有可比资格标准和措施的认知补救试验。所有参与者都接受了基线评估，包括当前认知、病前智商、社会心理功能和情绪症状严重程度的测量。我们估计并比较了规范性和特发性损伤的患病率，并检查了特发性入路与功能的关系。结果根据规范标准，根据采用的截止值，我们的健康样本中有13%-31%的人被归类为认知障碍。在计入病前智商后，具体损害率增加到37%-64%。两种方法之间的差异对于考虑的每个截止值（0.5和1 SD）都是显著的。即使在控制了残余情绪症状、人口统计学/临床变量和功能障碍分类之后，特发性认知障碍与社会心理功能显著相关。结论：对于相当比例的心境良好的双相障碍患者来说，使用标准方法表征认知障碍的常见做法可能低估了认知障碍的程度。考虑具体损害为认知试验和临床实践提供了另一种与功能相关的方法。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Acta Psychiatrica Scandinavica 医学-精神病学

CiteScore

11.20

自引率

3.00%

发文量

135

审稿时长

6-12 weeks

期刊介绍： Acta Psychiatrica Scandinavica acts as an international forum for the dissemination of information advancing the science and practice of psychiatry. In particular we focus on communicating frontline research to clinical psychiatrists and psychiatric researchers. Acta Psychiatrica Scandinavica has traditionally been and remains a journal focusing predominantly on clinical psychiatry, but translational psychiatry is a topic of growing importance to our readers. Therefore, the journal welcomes submission of manuscripts based on both clinical- and more translational (e.g. preclinical and epidemiological) research. When preparing manuscripts based on translational studies for submission to Acta Psychiatrica Scandinavica, the authors should place emphasis on the clinical significance of the research question and the findings. Manuscripts based solely on preclinical research (e.g. animal models) are normally not considered for publication in the Journal.