Delusional infestation: a clinical profile

Delusional infestation or delusional parasitosis is a form of monodelusional disorder, a condition sometimes encountered in psychiatric or primary care practice. The outcome of this condition is good when compliance can be ensured.

In the present study, a series of 50 consecutive cases of delusional infestation is reported.

A majority of cases (94%) had insidious onset. The duration of symptoms in all but 3 cases was 6 months or more. Twenty-eight cases presented with a delusion of infestation by insects over the body and 20 cases with a delusion of insects crawling over the scalp. Two cases had associated diabetes mellitus, 3 cases had leprosy, 2 cases had dementia, 5 cases had depression, and 4 cases presented with trichotillomania. Among the second generation antipsychotics, risperidone was used in 12 cases, olanzapine in 9 cases, amisulpride in 7 cases, etc. Thirty-four cases (68%) showed complete remission while receiving pharmacotherapy, 13 cases showed partial improvement, and 3 cases did not respond to treatment.

The study demonstrates the utility of second generation antipsychotics in the treatment of this disorder. Further studies are warranted to study the treatment and outcome of this important psychiatric disorder.