Jackson Felicia, Foti Dan, Kotov Roman, Perlman Greg, Mathalon Daniel H, Proudfit Greg Hajcak
Department of Psychology, Stony Brook University, Stony Brook, NY, United States.
Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States.
Schizophr Res. 2014 Dec;160(1-3):208-15. doi: 10.1016/j.schres.2014.09.039. Epub 2014 Oct 22.
Cognitive impairments and delusions are hallmarks of schizophrenia, and are thought to be due in part to abnormalities in semantic priming. The N400, a neural measure of semantic processing, is found to be reduced in schizophrenia. However, it is unclear if individuals with other psychoses (e.g., mood disorders or substance abuse with psychotic features) also show this impairment, and whether N400 reduction relates to real-world functioning and recovery.
Eighty-nine individuals from the Suffolk County Mental Health Project, a longitudinal study of first-admission psychosis, and 35 healthy adults were assessed using matched, related, and unrelated picture-word pairs to elicit the N400. Patients' real-world functioning, symptomatology, and recovery were tracked since first hospitalization; EEG assessment was completed during year 15 of the study.
Participants with schizophrenia had slower reaction times and reduced N400 to semantically incongruent stimuli relative to healthy participants. Schizophrenia and other psychoses did not differ on N400, suggesting that N400 abnormalities characterize psychosis broadly. When grouped by recovery status, patients who remained ill had a significantly blunted N400, while those who recovered did not differ from healthy adults. Few patients with schizophrenia achieved recovery; therefore recovery results are limited to the other psychosis group. Furthermore, reduced N400 and increased reaction times correlated with greater psychotic symptoms, worse global assessment of functioning scores, unemployment, and impaired social functioning.
Abnormalities in the N400 are not specific to schizophrenia; in addition, the N400 may be a useful neural correlate of recovery and real-world functioning across psychotic disorders.
认知障碍和妄想是精神分裂症的标志，部分原因被认为是语义启动异常。N400是一种语义加工的神经测量指标，在精神分裂症患者中发现其值降低。然而，尚不清楚患有其他精神病（如伴有精神病性特征的情绪障碍或物质滥用）的个体是否也表现出这种损害，以及N400降低是否与现实功能和康复有关。
来自萨福克郡心理健康项目（一项首次入院精神病的纵向研究）的89名个体和35名健康成年人使用匹配、相关和不相关的图片-单词对进行评估，以引出N400。自首次住院以来，对患者的现实功能、症状和康复情况进行跟踪；脑电图评估在研究的第15年完成。
与健康参与者相比，精神分裂症患者对语义不一致刺激的反应时间更慢，N400降低。精神分裂症患者和其他精神病患者在N400上没有差异，这表明N400异常是精神病的普遍特征。按康复状态分组时，仍患病的患者N400明显减弱，而康复的患者与健康成年人没有差异。很少有精神分裂症患者康复；因此，康复结果仅限于其他精神病组。此外，N400降低和反应时间增加与更严重的精神病症状、更差的整体功能评估得分、失业和社会功能受损相关。
N400异常并非精神分裂症所特有；此外，N400可能是跨精神病性障碍康复和现实功能的有用神经关联指标。
