An international study of the prevalence of substance use in patients with delusional infestation

To the Editor: Delusional infestation (DI) is a disorder characterised by the belief of being infested with living organisms or objects.1 Insects and worms are the most common concerns. Objects, such as fibers or threads, are increasingly reported by patients. DI can be primary or secondary to mental illness, physical illness, prescribed medication, and misuse of substances such as amphetamines, cannabis, codeine, cocaine, or opiates. Dermatologists are usually the specialists to whom a patient with DI is referred because patients believe that they have primarily a skin disease