Clozapine and Tardive Dyskinesia

Ms. A was a 33-year-old woman with a 16-year history of paranoid schizophrenia characterized by persistent auditory hallucinations, persecutory delusions, and negative symptoms. Initially, she was treated with haloperidol, 5 to 10 mg/day, for approximately 1 year and was then switched to fluphenazine decanoate, 37.5 mg intramuscularly every 2 weeks for 1 year; both treatments led to minimal response. She was subsequently given clozapine for her treatment-resistant schizophrenia. After an initial dose of 400 mg/day, her clozapine dose was gradually increased over a 1-year period to 875 mg/day. She eventually experienced remission of her auditory hallucinations and had significant improvement of her persecutory delusions and negative symptoms.

An assessment with the Abnormal Involuntary Movement Scale (5), performed before Ms. A started taking clozapine, revealed no evidence of dyskinetic movements. After 10½ years of treatment with clozapine, Ms. A was first noted to have mild repetitive involuntary jaw and tongue movements; she was given vitamin E, 800 IU b.i.d. The abnormal movements continued and gradually worsened. Her dose of clozapine was gradually reduced from 875 to 625 mg/day over 12 months. Ms. A’s psychiatric status remained stable, and the abnormal involuntary movements persisted unchanged.