No one knows for sure how common DP/DR is; it is not a well-studied condition. Data that exist suggest that as a stand-alone condition, Depersonalization/Derealization Disorder affects 1 percent of the population, about the same prevalence as schizophrenia. That may be a vast underestimate, as psychiatrists rarely screen for the condition and people are either reluctant to describe their experiences of DP/DR or have difficulty doing so. People typically experience symptoms for many years before their disorder is diagnosed.
Among psychiatric populations, depersonalization is far more common, occurring in up to 80 percent of patients. Clinicians who screen for the disorder observe that depersonalization may be the third most common psychiatric symptoms, after anxiety and depressed mood.