Public Release: 

Global study finds psychotic experiences infrequent in general population

The JAMA Network Journals

Psychotic experiences were infrequent in the general population, with an average lifetime prevalence of ever having such an episode estimated at 5.8 percent, according to an article published online by JAMA Psychiatry.

Interest in the epidemiologic landscape of hallucinations and delusions has grown because these psychotic experiences (PEs) are reported by a sizable minority of the population. Some have called for more fine-grained analyses of PEs to guide the field.

Researcher John J. McGrath, Ph.D., M.D., of the University of Queensland, Australia, and coauthors examined data collected in the World Health Organization World Mental Health surveys to explore detailed epidemiologic information about PEs. The data came from 18 countries across North and South America, Africa, the Middle East, Asia, the South Pacific and Europe. Respondents included 31,261 adults who were asked about the prevalence and frequency of PEs (two hallucinatory experiences and four delusional experiences).

The study found the lifetime prevalence of at least one PE was reported by 5.8 percent of the 31,261 survey respondents. The lifetime prevalence of any hallucinatory experience (HE) was 5.2 percent and of any delusional experience (DE) was 1.3 percent.

Lifetime prevalence estimates of PEs were higher among women (6.6 percent) than men (5 percent) and higher among those individuals who lived in middle-income (7.2 percent) and high-income (6.8 percent) countries than in low-income countries (3.2 percent), according to the results.

These psychotic experiences were infrequent with 32.2 percent of respondents with lifetime PEs reporting only one episode and an additional 31.8 percent of respondents with lifetime PEs having experienced two to five episodes.

"We have provided, to our knowledge, the most comprehensive description of the epidemiologic landscape of PEs published to date. Although the lifetime prevalence of PEs is 5.8 percent, these events are typically rare. ... The research community needs to leverage this fine-grained information to better determine how PEs reflect risk status. Our study highlights the subtle and variegated nature of the epidemiologic features of PEs and provides a solid foundation on which to explore the bidirectional relationship between PEs and mental health disorders," the study concludes.

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(JAMA Psychiatry. Published online May 27, 2015. doi:10.1001/jamapsychiatry.2015.0575. Available pre-embargo to the media at http://media.jamanetwork.com.)

Editor's Note: The study includes conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

Media Advisory: To contact corresponding author John J. McGrath, Ph.D., M.D., email j.mcgrath@uq.edu.au.

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