Abstract： Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive genetic disease caused by a deficiency of mitochondrial enzyme sterol 27-hydroxylase. It is rare and features concealed onset, diverse clinical manifestations, and an average diagnostic cycle of 23 years. This case is a who presented with psychiatric symptoms as the initial symptoms. During the treatment process, gait instability gradually became apparent, with unsatisfactory treament efficacy after switching several medications. He had a history of chronic diarrhea in his childhood, and physical examination revealed bilateral nodules of the Achilles tendon. Neurological examination showed decreased muscle tone and ataxia. The head MRI and left ankle joint MR plain scan showed abnormal signals. Genetic testing revealed a CYP27A1 sequence mutation, diagnosed as "cerebrotendinous xanthomatosis". The patient was treated with "geese deoxycholic acid capsules" combined with antipsychotic drugs, and was "improved"and discharged. This article reports the clinical data of the patient and reviews relevant literature, aiming to help improve the screening ability of psychiatrists for this disease and provide empirical guidance for subsequent clinical work.