A systematic review and meta-analysis found that the rate of psychotic experiences (PEs) is 2 out of every 100 people yearly. These findings were published in Schizophrenia Bulletin.
A PE is a hallucination or delusion occurring outside of a psychotic disorder. Individuals who have a PE are at a 4-fold increased risk for developing psychosis and a 3-fold higher risk for mental disorders.
As no reviews about the prevalence of PEs have been conducted in the last 2 decades, investigators at the Royal College of Surgeons in Dublin, Ireland searched publication databases from inception through January 2023 to conduct this updated review. A total of 16 publications about PE incidence and 29 about PE persistence were included in this analysis.
Among a pooled sample size of 56,089 individuals, the incidence rate (IR) of PEs was 0.0225 (95% CI, 0.0129-0.0322) per person-year (I2, 98.4%). This IR equates to 2 people out of 100 reporting a first PE event each year.
Stratified by age group, the IRs were 0.0290 per person-year (py) for children aged younger than 13 years, 0.0455 per py for adolescents aged 13 to 17 years, 0.0155 per py for adults aged 18 to 64 years, and 0.0125 per py for older adults aged over 64 years. These rates differed significantly between groups (P =.0043).
The rate of PEs did not differ significantly between studies that relied on self-reporting or clinical interview (P =.70), in studies classified as enriched or not enriched (P =.57), in studies conducted in English or other languages (P =.39), or when using measures initially designed in English or other languages (P =.61).
With a pooled sample size of 81,847 individuals, among those who reported a PE, 31% (95% CI, 26.65%-35.35%) reported a second PE within a given year (I2, 86.16%).
The rate of PE persistence did not differ significantly on the basis of age (P =.43) and ranged between 28.2% among adults to 35.8% among adolescents. Similarly, persistence did not depend on self-report compared with clinical interview (P =.34), cohort or case-control study design (P =.59), enriched or not enriched samples (P =.99), or using measures initially designed in English compared with other languages (P =.7839). However, there was a significant effect (P =.034) of language, in which the persistence of PE was reported to be higher in studies conducted in English (35.78%) compared with other languages (27.24%).
This study may have been limited by the fact that most studies were conducted in Europe or North America, so data may not be generalizable for other less economically wealthy regions.
The study authors concluded, “We have found valuable estimates needed to determine if interventions are effective ie, incidence rate per person-year, which can be used to determine prevention, and persistence rate per year, which can be used to determine reduction. […] There is a growing body of literature on PEs but there is a need to expand beyond academic research, into clinical practice and preventative treatment, particularly in young people.”
Staines L, Healy C, Murphy F, et al. Incidence and persistence of psychotic experiences in the general population: systematic review and meta-analysis. Schizophr Bull. 2023:sbad056. doi:10.1093/schbul/sbad056