Alzheimer’s disease (AD) is a neurodegenerative disorder featuring the behavioral and psychological symptoms of dementia. Patients with early-onset AD that exhibits first as psychotic symptoms usually lack obvious cognitive impairment, so they may be misdiagnosed with late-onset schizophrenia. We report a patient who had prominent psychotic symptoms at the age of 60 and was initially diagnosed with very-late-onset-schizophrenia-like psychosis. Psychotic symptoms disappeared rapidly after treatment with olanzapine, and the patient later showed extrapyramidal symptoms and decline in cognitive function. Brain magnetic resonance imaging (MRI) showed frontotemporal atrophy, and positron emission tomography (PET) showed extensive areas of hypometabolism in the frontal cortex and head of the caudate nucleus. The patient’s SORL1 gene was found to carry a heterozygrous mutation (c.296A > G). The patient was eventually diagnosed with early-onset AD. Our case suggests that clinicians should consider the possibility of early-onset AD in middle-aged or elderly patients whose first symptoms are the behavioral and psychological symptoms of dementia. To distinguish early-onset AD from late-onset schizophrenia, clinicians should evaluate cognitive function, perform MRI and PET, and search for SORL1 mutations.

中文翻译：

---

早发性阿尔茨海默氏病患者首发精神病症状的病例报告。

阿尔茨海默氏病（AD）是一种神经退行性疾病，具有痴呆的行为和心理症状。最早表现为精神病症状的早发性AD患者通常缺乏明显的认知障碍，因此他们可能被误诊为迟发性精神分裂症。我们报道了一名患者，该患者在60岁时出现了明显的精神病症状，最初被诊断出患有迟发性精神分裂症样精神病。用奥氮平治疗后，精神病症状迅速消失，患者随后出现锥体束外症状和认知功能下降。脑磁共振成像（MRI）显示额颞萎缩，正电子发射断层扫描（PET）显示额叶皮层和尾状核头部广泛的低代谢区域。发现患者的SORL1基因带有杂合子突变（c.296A> G）。该患者最终被诊断出患有早发性AD。我们的案例表明，临床医生应考虑初次症状为痴呆症的行为和心理症状的中年或老年患者发生AD的可能性。为了区分早发性精神分裂症和早发性精神分裂症，临床医生应评估认知功能，进行MRI和PET并寻找SORL1突变。