Psychotic Disorders: Lifetime Prevalence

Editor, Primary Psychiatry and Psychiatry Weekly, Professor of Psychiatry, New York University School of Medicine

A newly published study (Perälä P, Suvisaari J, Saarni SI, et al. Lifetime prevalence of psychotic and bipolar I disorders in a general population. Arch Gen Psychiatry. 2007;64:19-28.) reports that the lifetime prevalence of psychosis may be 2-fold greater than was previously believed. Using rigorous screening and diagnostic methods, investigators in Finland looked for subjects with a diagnosis of any psychotic or bipolar I disorder in nationally representative sample of persons >30 years of age. The lifetime prevalence of all psychotic disorders was found to be between 3.06% and 3.48%. Earlier estimates ranged from .75% to 1.5%.

Increasing Use of Atypical Antipsychotics

These new results come at a time when questions have been raised about the increasing use of the newer treatments for psychosis—the serotonin-dopamine reuptake inhibitors—also known as the atypical or second generation antipsychotic drugs.

The finding of the higher prevalence of psychosis might help to explain why they are being widely prescribed.

This study is the largest general population survey of the prevalence of psychotic disorders and the first to report the prevalence rates of specific psychotic disorders separately.

One of the findings from this study highlights the dilemma that clinicians face in managing psychosis in the elderly. The Finnish data show, for example, that the prevalence of psychotic disorders is highest among those >65 years of age, with the lifetime prevalence of psychotic disorders due to a general medical condition starting to rise at 65 years of age. The lifetime rate is 1.71% among those >80 years of age. Approximately 93% of those with a psychotic disorder due to a medical condition in the group >80 years of age had dementia.

No antipsychotic is FDA-approved as a treatment for dementia-related psychotic symptoms. In fact, there is a “Boxed Warning” in the product information for all atypical antipsychotic drugs stating that “elderly patients with dementia-related psychosis treated with atypical antipsychotic drugs are at an increased risk (1.6–1.7 times) of death compared with placebo (4.5% to 2.6%, respectively).”

As a result of the data presented in this study, more research and more guidance on practical considerations when medicating dementia patients need to be forthcoming. In addition, the finding of such high rates of psychosis in the general population may explain the current popularity of atypical antipsychotics. The availability of these drugs seems to have lowered the threshold at which many clinicians are willing to treat psychotic disorders.

Disclosure: Dr. Sussman has received honoraria from AstraZeneca, Bristol-Myers Squibb, and GlaxoSmithKline.