Objective:Cognitive dysfunction cut across diagnostic categories and is present in both schizophrenia and bipolar disorder, although with considerable heterogeneity in both disorders. This study examined if distinct cognitive subgroups could be identified across schizophrenia and bipolar disorder based on the intellectual trajectory from the premorbid phase to after illness onset.Method:Three hundred and ninety-eight individuals with schizophrenia (n = 223) or bipolar I disorder (n = 175) underwent clinical and neuropsychological assessment. Hierarchical and k-means cluster analyses using premorbid (National Adult Reading Test) and current IQ (Wechsler Abbreviated Scale of Intelligence) estimates were performed for each diagnostic category, and the whole sample collapsed. Resulting clusters were compared on neuropsychological, functional, and clinical variables. Healthy controls (n = 476) were included for analyses of neuropsychological performance.Results:Cluster analyses consistently yielded three clusters: a relatively intact group (36% of whole sample), an intermediate group with mild cognitive impairment (44%), and an impaired group with global deficits (20%). The clusters were validated by multinomial logistic regression and differed significantly for neuropsychological, functional, and clinical measures. The relatively intact group (32% of the schizophrenia sample and 42% of the bipolar sample) performed below healthy controls for speeded neuropsychological tests.Conclusions:Three cognitive clusters were identified across schizophrenia and bipolar disorder using premorbid and current IQ estimates. Groups differed for clinical, functional, and neuropsychological variables, implying their meaningfulness. One-third of the schizophrenia sample belonged to the relatively intact group, highlighting that neuropsychological assessment is needed for the precise characterization of the individual.

中文翻译：

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精神分裂症和双相情感障碍的认知异质性：智力轨迹的聚类分析

目的：认知功能障碍跨越诊断类别，存在于精神分裂症和双相情感障碍中，尽管在这两种疾病中具有相当大的异质性。本研究根据从发病前阶段到发病后的智力轨迹，检查是否可以在精神分裂症和双相情感障碍中识别出不同的认知亚群。方法：398 名精神分裂症患者（n= 223) 或双相 I 型障碍 (n= 175) 接受了临床和神经心理学评估。分层和ķ- 使用病前（全国成人阅读测试）和当前 IQ（韦氏智力缩写量表）估计值对每个诊断类别进行均值聚类分析，整个样本崩溃。在神经心理学、功能和临床变量上比较产生的集群。健康对照 (n= 476) 被纳入神经心理表现分析。结果：聚类分析始终产生三个聚类：一个相对完整的组（占整个样本的 36%）、一个具有轻度认知障碍的中间组（44%）和一个具有全球赤字（20%）。这些集群通过多项逻辑回归进行了验证，并且在神经心理学、功能和临床测量方面存在显着差异。相对完整的组（32% 的精神分裂症样本和 42% 的双相情感障碍样本）在快速神经心理学测试中表现低于健康对照组。结论：使用发病前和当前的 IQ 估计，确定了精神分裂症和双相情感障碍的三个认知集群。各组在临床、功能和神经心理学变量方面存在差异，这意味着它们的意义。