Primary delusional parasitosis treated with olanzapine

Area of Science:

• Psychiatry
• Pharmacology

Background:

• Delusional parasitosis (DP) is a rare psychiatric disorder affecting middle-aged and elderly individuals.
• It can present as primary DP or secondary to other conditions.
• Pimozide, a typical antipsychotic, was the traditional treatment, but atypical antipsychotics offer better tolerability.

Purpose of the Study:

• To report the first documented case of successful long-term olanzapine monotherapy for primary delusional parasitosis.
• To evaluate the efficacy and need for maintenance treatment of olanzapine in primary DP.
• To review existing literature on atypical antipsychotic treatment for primary DP.

Main Methods:

• A case report of a 77-year-old woman with primary DP.
• Treatment with low-dose olanzapine (2.5 mg daily).
• A 3.5-year follow-up period in a psychiatric outpatient setting.
• A comprehensive literature review of primary DP treated with atypical antipsychotics.

Main Results:

• The patient experienced a marked response to olanzapine monotherapy.
• Sustained remission was observed over the 3.5-year follow-up period, demonstrating the need for maintenance treatment.
• The review indicated limited but emerging evidence for atypical antipsychotics in primary DP.

Conclusions:

• Low-dose olanzapine is a viable and effective alternative treatment for primary delusional parasitosis, particularly in elderly patients.
• Age-adapted doses of olanzapine should be considered for managing primary DP.
• Long-term maintenance therapy may be necessary for sustained remission.