PARIS – Ever wonder, when encountering an occasional patient afflicted with delusional infestation, just how common this mental disorder is?
John J. Kohorst, MD, and his coinvestigators at the Mayo Clinic in Rochester, Minn., have the evidence-based answer.
The age- and sex-adjusted point prevalence of delusional infestation among Olmsted County, Minn., residents on the final day of 2010 was 27.3 cases per 100,000 person-years, he reported at the annual congress of the European Academy of Dermatology and Venereology.
“This is the than previously suspected,” according to the dermatologist.
He and his coinvestigators retrospectively analyzed data from the Rochester Epidemiology Project. They identified 22 female and 13 male county residents with a firm diagnosis of delusional infestation, also known as delusional parasitosis. This disorder is marked by a patient’s fixed false belief that they are infested with insects, worms, or other pathogens.
The prevalence was similar in men and women. The most striking study finding was how heavily age-dependent delusional infestation was. Before age 40, the prevalence was a mere 1.2 cases per 100,000 person-years. Among 40- to 59-year-old Olmsted County residents, it was 35/100,000, jumping to 64.5/100,000 in the 60- to 79-year-old age bracket, then doubling to 130.1 cases per 100,000 person-years in individuals aged 80 or older.
Dr. Kohorst reported having no financial conflicts regarding his study, conducted free of commercial support.