Atypical anti‐psychotics in Delusional Parasitosis: a retrospective case series of 20 patients

BACKGROUND: Delusional Parasitosis (DP) is a relatively uncommon condition wherein there is a fixed belief that one is infested with living organisms despite a lack of medical evidence of such infestation. Pimozide has been mooted as specific for the treatment of this condition. Atypical anti-psychotics have received attention in recent years. METHODS: We describe the clinical features and treatment responses in a retrospective review of 20 cases treated at this department over a 5 year period, and selectively review the literature. RESULTS: The majority were treated with atypical anti-psychotics and all subjects who followed up showed varying degrees of clinical improvement irrespective of the anti-psychotic used. CONCLUSION: The evidence for pimozide as first line drug in DP is limited to one small, non-randomized placebo-controlled trial. DP responds well to most anti-psychotics. Prospective randomized trials are needed to clarify optimal treatment of this relatively rare but debilitating condition.