[Author Affiliation]Shiyan Chen. Otolaryngology Department, Fuzhou General Hospital of Nanjing Command, PLA, Fuzhou, Fujian 350025, China.Hongxun Gong. Otolaryngology Department, Fuzhou General Hospital of Nanjing Command, PLA, Fuzhou, Fujian 350025, China.Xianming Chen. Otolaryngology Department, Fuzhou General Hospital of Nanjing Command, PLA, Fuzhou, Fujian 350025, China.Address correspondence to: Xianming Chen, Otolaryngology Department, Fuzhou General Hospital of Nanjing Command, PLA, Fuzhou, Fujian 350025, China, E-mail: fuzongerbihou@163.comTo The Editor:Quetiapine is currently being used to treat schizophrenia and bipolar disorder. We report a case in which quetiapine acted as a possible tic inducer during treatment of bipolar disorder, although there have been several case reports on the successful use of quetiapine for the treatment of Tourette's syndrome in children and adolescents (Copur et al. 2007). This is probably the first such reported case in a pediatric bipolar patient.Case ReportL, a 16-year-old boy without any other past psychiatric history, was overactive for ∼5 weeks, and his mother thought him, mad. She said that he spent all his money to buy lots of unnecessary things. His teachers thought that he appeared restless all day without getting tired. He frequently felt more self-confident than usual and always said he could be in charge of a country. He talked rapidly with abrupt changes from topic to topic, and was difficult to interrupt during the outpatient clinical examination. No abnormality was detected on a brain MRI scan or electroencephalogram (EEG), or during laboratory examination. No childhood or family history of tic disorder was found. Because L's history also revealed a depression episode 2 years earlier, he was diagnosed with bipolar disorder type I according to the Kiddie Schedule for Affective Disorders and Schizophrenia for School-Aged Children--Present and Lifetime Version (K-SADS-PL). His score on the Young Mania Rating Scale was 44.Quetiapine was started at 50mg/day for the first 2 days. The dose of quetiapine was increased progressively by 50 mg every 4 days. The patient's symptoms resolved completely when quetiapine was titrated up to 600 mg/day. His father told us afterwards that he occasionally blinked his eyes once the quetiapine dose was titrated to 150 mg/day. Recurrent episodes of ''tightening'' of his eyes, nose, and the corner of his mouth increased in frequency, ultimately occurring thousands of times per day when quetiapine was titrated up to 600 mg/day. When the patient came to our clinic again, we used the Yale Global Tic Severity Scale to measure the severity of tic symptoms, and the score was 40. …