Liping Yu ¹ Hui Xu ¹ Zhongliang Jiang ¹ Hanxue Yang ² Yonghua Cui ¹ Ying Li ^1*

• ¹ Beijing Children’s Hospital, Capital Medical University, Beijing, Beijing Municipality, China
• ² Beijing Language and Culture University, Beijing, Beijing Municipality, China

Background: Tic disorder, a chronic neurodevelopmental disorder that typically onsets during childhood, is characterized by sudden, involuntary, rapid, and non-rhythmic motor and vocal tics. Individuals with tic disorders often experience physical health issues. The purpose of our retrospective analysis was to elucidate the common comorbid physical diseases and mental disorders and their characteristics of outpatient children with tic disorders in a large public children's hospital in China over the past five years.Methods: Participants were outpatients with tic disorders who visited Beijing Children's Hospital, from January 1, 2018, to December 31, 2022. After the inclusion screening, a total of 523,462 patient visits were included in the analysis. Based on the International Classification of Diseases, 10th Revision (ICD-10) diagnostic system, we employed descriptive statistical analysis to examine the frequently co-occurring somatic diseases in patients with tic disorders, as well as the influence of variables such as age and seasonal variation on these comorbidities.The top five diseases of total outpatient visits were as follows：Respiratory diseases, Mental and behavioral disorders, Diseases of the eye and adnexal, Digestive disorders, Diseases of the skin and subcutaneous tissue. Among the top five comorbid disease system, the most commonly third-level classification of diseases were upper respiratory tract infections, attention deficit and hyperactivity disorder, conjunctivitis, dyspepsia, dermatitis. Respiratory system diseases experienced a peak in April, while the other four types of diseases reached their peak in August. Additionally, each disease system showed the lowest number of patient visits in February. Additional to the mental and behavioral disorders, the other four disease systems would experience a peak in medical visits between the ages of 4 and 6.Our study highlighted the most common physical diseases and mental disorders in tic disorders, namely the respiratory diseases, specifically upper respiratory tract infections, and mental and behavioral disorders, with ADHD being the most common co-occurring condition.