A Cross-Sectional Study on the Characteristics of Tardive Dyskinesia in Patients with Chronic Schizophrenia

BACKGROUND: Tardive dyskinesia (TD) is an abnormal involuntary movement disorder caused by patients’ long-term use of antipsychotic medication. It diminishes the social functioning of patients with mental disorders, thereby affecting their compliance with antipsychotic medication. The cause and nosogenesis of TD remains unclear; furthermore, because the presentation differs greatly among individuals it often goes undiagnosed or can be easily misdiagnosed. The present study aims to evaluate the abnormal movement patterns in patients with TD, and analyze the differences among different TD patterns, in order to seek effective methods of preventing, diagnosing and treating TD. AIMS: To describe the movement patterns of patients with chronic schizophrenia with TD, and analyze their clinical characteristics and risk factors. METHODS: A cross-sectional study was carried out on a psychiatric unit of the Xuhui Mental Health Center with inpatients who had chronic schizophrenia as participants. Abnormal Involuntary Movement Scale (AIMS) was employed to screen for patients with schizophrenia who also had TD. These patients’ movement disorders were evaluated, and they were divided into groups based on their movement patterns. Positive and Negative Syndrome Scale (PANSS) was used to assess the psychotic symptoms of patients, collect clinical information, compare the differences between the two groups and analyze the clinical characteristics and risk factors of TD. RESULTS: (1) A total of 448 patients met the inclusion criteria for chronic schizophrenia with 46 in the TD group and 402 in the control group. After the TD group and the control group was compared, significant differences were seen between the two groups in gender, age, total duration of illness, age of onset, dosage of antipsychotic medication (daily chlorpromazine equivalent), factor scores of negative symptoms on PANSS and PANSS total scores. (2) It was possible that age, factor scores of negative symptoms in PANSS, the amount of antipsychotic medication used (daily chlorpromazine equivalent) and gender are correlated with the occurrence of TD. (3) There were significant differences among the number of TD patients with movement disorders in facial and oral areas (67.4%), limbs (58.7%) and torso (37%). The AIMS scores corresponding with movement disorders in different parts of the body were also significantly different. (4) Comparing TD patients with single affected area and those with multiple affected areas, we found that they had significant differences in gender, age of onset, AIMS total scores, severity scores of abnormal movements and loss of range due to abnormal movements. CONCLUSION: (1) Compared to the control group, the TD group had more men, was older, had a longer duration of illness, later age of onset, generally took a higher dosage of antipsychotic medication and presented with more severe negative symptoms. It is possible that age, factor scores of negative symptoms on PANSS, dosage of antipsychotic medication (daily chlorpromazine equivalent) and gender are correlated with the occurrence of TD. (2) The occurrence of movement disorders in facial and oral areas for patients with chronic schizophrenia with TD was the most frequent, and the symptoms were the most severe. (3) Compared to TD patients with a single affected area, TD patients with multiple affected areas may have an earlier age of onset, more severe movement disorders, and more setbacks in their movement and functioning.