SIR: To the best of our knowledge, this is the first report of a schizophrenic patient with panic attacks under conventional neuroleptic treatment who experienced full remission of these episodes after switching to risperidone.

Ms. A, a 28-year-old woman with a 6-year history of schizophrenia, had been treated with conventional neuroleptics, including haloperidol and fluphenazine. Her psychotic symptoms had been completely controlled on a regimen of haloperidol 6—8 mg/day and biperiden 3mg/day. However, in 1998 she suddenly experienced a severe panic attack with anxiety, shortness of breath, racing heart, choking, sweating, and fear of dying, without reemergence of psychosis. She came to our hospital and was given a prescription of alprazolam to be taken as needed in aborting the panic attacks. Although she experienced partial relief, her panic attacks continued to occur 3 to 4 times per month during the following 5 months. In this period, she developed no psychotic symptoms and showed no extrapyramidal side effects such as akathisia, which are well known to coincide with panic attacks. She had to quit her job as a bakeshop assistant and could not go out unaccompanied. She began taking alprazolam on a regular basis and increased the dose up to 3.2 mg/day by herself, resulting in disappearance of panic symptoms, but she could not tolerate this dose because of sedation. Alprazolam was decreased gradually to the dose at which she did not feel sedation, 1.2 mg/day. However, this dose of alprazolam could not control her panic symptoms. We decided to replace haloperidol 6 mg/day with risperidone 3mg/day, while keeping the dose of alprazolam at 1.2 mg/day. This switching from haloperidol to risperidone led to full remission of her panic symptoms, and we could successfully discontinue alprazolam without reemergence of panic attacks and psychosis. Benefit persisted on the regimen of risperidone 3 mg/day and biperiden 3mg/day at 1-year follow-up.

The anxiolytic agents such as alprazolam and other benzodiazepines have been shown to be effective in treating panic attacks in patients with schizophrenia;⁺¹ however, the panic symptoms in this case were difficult to control with alprazolam because of side effects. There have been some reports suggesting that atypical antipsychotics, including risperidone and olanzapine, have greater efficacy for anxiety symptoms accompanying schizophrenia than haloperidol, a conventional neuroleptic.^+2,+3 This anxiolytic action of risperidone might have contributed to remission of panic attacks in our schizophrenic patient. However, Mandalos and Szarek reported the case of a patient with schizophrenia who developed panic attacks after switching from thioridazine to olanzapine.⁺⁴ The reason for the difference in effect on panic attacks in schizophrenic patients between risperidone and olanzapine is unknown.

Panic attacks and schizophrenic symptoms are common comorbid conditions;^+1,+5 however, less evidence is available concerning pharmacological strategy for panic attacks in patients with schizophrenia. Although our observation should be considered preliminary, the promising result in our patient after switching to risperidone warrants further study to evaluate the potential benefit of this strategy for schizophrenic patients suffering from panic attacks under conventional neuroleptic treatment.