Clinical Features, Etiological Spectrum, and Outcomes of Neurological Patients Initially Presenting with Psychiatric Symptom

Background Neurological disorders can manifest with psychiatric symptoms as the initial presentation (PSIP), leading to diagnostic challenges and risk of delayed treatment. Data on the clinical trajectory of this specific patient population remain limited. Methods This retrospective cohort study analyzed 51 inpatients admitted to the Department of Neurology between 2019 and 2023, selected based on PSIP at admission. We extracted and analyzed demographic, clinical, laboratory, neuroimaging, and outcome data from electronic medical records. Results The cohort (mean age 56.5 ± 17.9 years; 39.2% female) predominantly exhibited nonspecific agitation and disturbed behavior (60.8%) rather than classic psychiatric syndromes. Acute onset was common (92.2%). Notably, 16 patients (31.4%) presented with isolated psychiatric symptoms without neurological signs or fever. Hyponatremia was a frequent finding (23.5%). Cerebrospinal fluid (CSF) abnormalities and brain MRI lesions were detected in 57.8% and 60.0% of patients, respectively. The leading etiologies were CNS infections (56.9%), predominantly viral encephalitis, followed by cerebrovascular diseases (15.7%) and autoimmune encephalitis (9.8%). Subgroup analysis of viral encephalitis patients revealed that those with PSIP had significantly higher rates of hyponatremia (42.9% vs. 14.7%, p = 0.007) and poorer outcomes (61.9% vs. 90.5% good outcome, p = 0.003) compared to those without PSIP, despite similar profiles in other clinical markers. Conclusion PSIP is a critical clinical scenario where underlying neurological disorders, particularly viral encephalitis, are common. Hyponatremia emerges as a key biomarker suggesting an organic etiology. The absence of neurological signs does not rule out a serious neurological condition. Early comprehensive investigation, including CSF analysis and neuroimaging, is essential for timely diagnosis and improved prognosis.