TARDIVE DYSKINESIA AND "RABBIT SYNDROME": DIFFERE NTIAL DIAGNOSIS IN OROFACIAL MOVEMENT DISORDERS INDUCED BY PSYCHOTROPIC DRUGS

Resumo

Introduction: Psychotropic drugs, especially antipsychotics, are associated with the development of extrapyramidal effects resulting from dopaminergic dysfunction in the basal ganglia, including movement disorders with orofacial manifestations. Among these manifestations, tardive dyskinesia and "rabbit syndrome" stand out, frequently confused due to clinical overlap, but with relevant differences regarding pathophysiology, onset, and therapeutic response. These disorders can lead to functional impairments, impacting communication, feeding, and quality of life. Objectives: To comparatively analyze tardive dyskinesia and "rabbit syndrome," emphasizing their differences in onset, clinical manifestations, diagnosis, treatment, and orofacial functional impact. Materials and Methods: This is a narrative literature review based on studies published in the last five years and indexed in the PubMed database. Articles addressing psychotropic movement disorders were included, with an emphasis on tardive dyskine sia and "rabbit syndrome." The search strategy included descriptors related to "tardive dyskinesia", "rabbit syndrome" and "drug -induced movement disorders", prioritizing clinical studies, systematic reviews, and recent guidelines. Results: Tardive dyskine sia is associated with prolonged use of dopaminergic blockers and involves mechanisms such as hypersensitivity of dopaminergic receptors and alterations in basal ganglia circuits. Additional alterations involving glutamatergic and GABAergic systems also contribute to its pathophysiology. Clinically, it is characterized by involuntary, stereotyped, and choreiform movements, frequently involving the lips, tongue, and jaw, and can compromise functions such as speech, chewing, and swallowing. Furthermore, the p sychosocial impact is significant, with stigma and reduced quality of life, which may persist even after withdrawal of the causative agent, reflecting the complexity of the clinical picture. In contrast, "rabbit syndrome" has an earlier onset and is freque ntly associated with drug -induced Parkinson's disease. It is characterized by rhythmic, rapid, and vertical movements of the perioral region, without significant involvement of the tongue, which constitutes an important criterion for clinical differentiation. This condition is frequently associated with signs such as rigidity and bradykinesia, and shows a good response to anticholinergics, unlike tardive dyskinesia. Besides antipsychotics, other drugs may be involved in the development of abnormal orofacial movements. Differential diagnosis requires detailed analysis of the movement pattern and medication history. Thus, tardive dyskinesia presents more complex and distributed movements, while "rabbit syndrome" presents a more restricted and rhythmic pattern. Coexistence between the disorders can occur, increasing the complexity of the diagnosis. Therefore, therapeutic management strategies include medication adjustment and specific pharmacological interventions, since VMAT2 (Vesicular Monoamine Transporter 2) inhibitors represent an effective approach for tardive dyskinesia, while anticholinergics are more indicated in "rabbit syndrome". Given the above, clinical management should be individualized and involve continuous monitoring. Conclusion: Tardive dyskinesia and "rabbit syndrome" present distinct clinical characteristics, despite being frequently confused. Differentiation based on movement pattern, tongue involvement, symptom onset, and therapeutic response is essential for proper management. Early recogni tion contributes to reducing functional impact and improving prognosis.