Treatments for Primary Delusional Infestation: Systematic Review (Preprint)

Abstract

BACKGROUND Delusional infestation (DI) is a rare delusional disorder characterized by the fixed belief that one is infested with parasites, worms, insects, and other organisms. Although DI is a psychiatric condition, patients often consult dermatologists with skin findings, and it is currently unclear what treatments are recommended for this disorder. OBJECTIVE To systematically review and describe the treatments and management of patients presenting with primary DI. METHODS A systematic search was conducted using Ovid on MEDLINE, Embase, PsychInfo, and the Cochrane Register of Clinical Trials. Relevant data including treatment, dosage, response, adherence, and side effects were extracted and analyzed. RESULTS A total of 15 case series were included, comprising 280 patients (53.3 mean age, 65.4% female) with DI. Overall, aripiprazole had the highest complete remission (CR) rate of 78.6%. Based on drug classes, selection serotonin reuptake inhibitors (SSRIs) were the most effective with a 57.1% CR and 42.9% partial remission (PR) rate in patients with comorbid depression, anxiety, or trichotillomania. Furthermore, atypical antipsychotics were more effective than typical antipsychotics (54.4% vs. 47.9% CR rate) with similar PR rates of 35%. CONCLUSIONS Atypical antipsychotics appear to be more effective than typical antipsychotics for the treatment of primary DI. Larger studies and randomized controlled trials are needed to evaluate the efficacy of pharmacological therapy for DI.