Objective: Low-level sensory disruption is hypothesized as a precursor to clinical and cognitive symptoms in severe mental disorders. We compared visual discrimination performance in patients with schizophrenia spectrum disorder or bipolar disorder with healthy controls, and investigated associations with clinical symptoms and IQ. Methods: Patients with schizophrenia spectrum disorder (n=32), bipolar disorder (n=55) and healthy controls (n=152) completed a computerized visual discrimination task. Participants responded whether the latter of two consecutive grids had higher or lower spatial frequency, and discrimination thresholds were estimated using an adaptive maximum likelihood procedure. Case-control differences in threshold were assessed using linear regression, F-test and post-hoc pair-wise comparisons. Linear models were used to test for associations between visual discrimination threshold and psychotic symptoms derived from the PANSS and IQ assessed using the Matrix Reasoning and Vocabulary subtests from the Wechsler Abbreviated Scale of Intelligence (WASI). Results: Robust regression revealed a significant main effect of diagnosis on discrimination threshold (robust F=6.76, p=.001). Post-hoc comparisons revealed that patients with a schizophrenia spectrum disorder (mean=14%, SD=0.08) had higher thresholds compared to healthy controls (mean=10.8%, SD = 0.07, β = 0.35, t=3.4, p=0.002), as did patients with bipolar disorder (12.23%, SD=0.07, β= 0.21, t=2.42, p=0.04). There was no significant difference between bipolar disorder and schizophrenia (β=-0.14, t=-1.2, p=0.45). Linear models revealed negative associations between IQ and threshold across all participants when controlling for diagnostic group (β = -0.3, t=-3.43, p=0.0007). This association was found within healthy controls (t=-3.72, p=.0003) and patients with bipolar disorder (t=-2.53, p=.015), and no significant group by IQ interaction on threshold (F=0.044, p=.97). There were no significant associations between PANSS domain scores and discrimination threshold. Conclusion: Patients with schizophrenia spectrum or bipolar disorders exhibited higher visual discrimination thresholds than healthy controls, supporting early visual deficits among patients with severe mental illness. Discrimination threshold was negatively associated with IQ among healthy controls and bipolar disorder patients. These findings elucidate perception-related disease mechanisms in severe mental illness, which warrants replication in independent samples.

中文翻译：

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精神分裂症谱系和双相障碍患者的空间频率辨别：早期视觉处理缺陷和与智力相关的证据

目的：假设低水平的感觉障碍是严重精神障碍临床和认知症状的先兆。我们将精神分裂症谱系障碍或双相障碍患者的视觉辨别能力与健康对照进行了比较，并研究了与临床症状和智商的关联。方法：精神分裂症谱系障碍患者 (n=32)、双相障碍患者 (n=55) 和健康对照组 (n=152) 完成了计算机视觉识别任务。参与者回答两个连续网格中的后者是否具有更高或更低的空间频率，并且使用自适应最大似然程序估计区分阈值。使用线性回归、F 检验和事后成对比较来评估阈值的病例对照差异。使用线性模型来测试视觉辨别阈值与源自 PANSS 的精神病症状之间的关联，以及使用 Wechsler 智能简写量表 (WASI) 的矩阵推理和词汇子测试评估的 IQ。结果：稳健回归揭示了诊断对辨别阈值的显着主效应（稳健 F=6.76，p=.001）。事后比较显示，与健康对照相比，精神分裂症谱系障碍患者（平均值 = 14%，SD = 0.08）具有更高的阈值（平均值 = 10.8%，SD = 0.07，β = 0.35，t = 3.4，p = 0.002 )，双相情感障碍患者也是如此（12.23%，SD=0.07，β=0.21，t=2.42，p=0.04）。双相情感障碍和精神分裂症之间没有显着差异（β=-0.14，t=-1.2，p=0.45）。当控制诊断组时，线性模型显示所有参与者的智商和阈值之间存在负相关（β = -0.3，t=-3.43，p=0.0007）。这种关联在健康对照 (t=-3.72, p=.0003) 和双相情感障碍患者 (t=-2.53, p=.015) 中发现，并且在阈值上的 IQ 交互作用没有显着组 (F=0.044, p =.97）。PANSS 域得分与区分阈值之间没有显着关联。结论：精神分裂症谱系或双相障碍患者比健康对照组表现出更高的视觉辨别阈值，支持严重精神疾病患者的早期视觉缺陷。在健康对照和双相情感障碍患者中，辨别阈值与智商呈负相关。