| Background The etiology of obsessive-compulsive disorder (OCD) is complex, and the clinical manifestations are highly heterogeneous. OCD patients with different age of onset have differences in clinical symptoms and etiology. Currently, research on inpatients with early- and late-onset OCD is limited. Objective To explore the differences in clinical characteristics between early- and late-onset OCD inpatients,and the factors affecting the onset age of OCD, in order to provide reference for early screening and treatment of OCD patients. Methods The medical records of 540 inpatients with OCD who were hospitalized at the Affiliated Brain Hospital of Nanjing Medical University from March 2012 to March 2023 were collected. Divide patients into early-onset group (n=310) and late-onset group (n=230) based on the onset age of 18 years old, and compare the differences in demographic data and clinical symptoms between the two groups. Analyzing the factors affecting the onset age of OCD using a binary logistic regression model. Results compared with the late-onset group, in terms of demographic data, the early-onset group had a higher proportion of males (P<0.01), single individuals (P<0.01), positive family history (P<0.05), and comorbidities with other mental illnesses (P<0.01). There were significant differences in occupational composition (P<0.05), education level (P<0.05), onset age (P<0.05), age at hospitalization (P<0.05), and types of obsessive-compulsive symptoms (P<0.05) between the two groups; In terms of clinical symptoms, the early onset group had a higher proportion of compulsive thinking (P<0.05), sorting (P<0.05), and ritualized symptoms (P<0.05), while the proportion of examination (P<0.05) and cleaning (P<0.05) symptoms was relatively low. In terms of risk factors, comorbid neurodevelopmental disorder, comorbid affective disorder, family history of schizophrenia, and family history of affective disorder are independent risk factors that affect the onset age of OCD inpatients (OR=19.587, 1.830, 3.065, 4.431, all P<0.05). Among them, comorbid neurodevelopmental disorder is the core factor that affects the onset age of OCD inpatients, and women are protective factors for early-onset patients (OR=0.417, P<0.01).. Conclusion There are differences in demographic data and clinical symptom characteristics between early- and late-onset OCD inpatients, and comorbid neurodevelopmental disorders are the core risk factors affecting the onset age of OCD inpatients. |