Delusional parasitosis with folie à deux: A case series.

Delusional parasitosis (DP) is characterized by single hypochondriacal delusion in which patient feels he/she is infested with insects. The authors present a case series of three cases of DP with shared psychotic disorder (folie à deux) in which one individual developed a delusional belief in the context of a close relationship with another person or people who already had an established delusional idea. All patients of DP were assessed in the outpatient department of Psychiatry of a tertiary care hospital. Diagnosis of DP was made on detail clinical history and supporting clinical findings. All our primary cases had DP and the accompanying relatives of our patients had folie à deux as they shared the belief of parasite infestation which was firm and persisted despite evidence to the contrary. The primary cases of delusional parasitosis responded well to oral risperidone. The intensity of the belief in the secondary person also reduced with improvement in the symptoms of the patients.