A Cohort-Based Study of Patients With Delusional Infestation: Characterizing the Patient Population

Area of Science:

• Psychodermatology
• Epidemiology
• Mental Health

Background:

• Delusional infestation (DI) is a rare psychodermatologic disorder with poorly understood epidemiology and management.
• Current trends in patient characteristics, presentation, and treatment require investigation.

Purpose of the Study:

• To investigate a recent cohort of delusional infestation patients.
• To understand current trends in patient characteristics, presentation, and management of DI.

Main Methods:

• Retrospective chart review of 81 DI patients from January 2021 to May 2024.
• Inclusion criteria: DSM-5 DI diagnosis, 1-month delusion history.
• Data collected on demographics, presentation, diagnostics, comorbidities, and treatments.

Main Results:

• Incidence of DI increased twofold (59.5/100,000 person-years), with 84% female predominance.
• Mean age at onset 51.5 years, with a 3-year diagnostic delay.
• Common delusions involved parasites (24%) and bugs (22%). Depression (58%) and anxiety (53%) were frequent comorbidities, with limited psychiatric consultation (31%).
• Treatment response was modest: antiparasitics (26% improved), second-generation antipsychotics (12% improved), first-generation antipsychotics (18% improved).

Conclusions:

• A significant increase in DI incidence and female predominance observed.
• Living infestation delusions (parasites, bugs) are most common.
• Pharmacotherapy for DI shows modest efficacy, necessitating further research into optimal management strategies.