A Systematic Review of the Psychotic-like Experiences Self-report Measurements for the General Population

In this systematic review, we evaluate the quality of measurements used to assess psychotic-like experiences (PLEs, ie, hallucinations, positive schizotypy, and delusions).

Following a systematic search, we included 170 validation articles that assessed measures of hallucinations, positive schizotypy, and delusions in the general population. We then assessed the methodological quality of the scales using COSMIN guidelines.

The results suggest that many of the scales for PLEs commonly used for the general population exhibit variability in their measurement properties, with concerns regarding structural validity and cross-cultural applicability. Internal consistency was typically moderate or high, but reliability was frequently not measured. There were only 5 studies that mentioned evaluation of content validity, which mostly consisted of experts' evaluation of the items. Overall, 11 out of 55 included scales showed satisfactory results.

Improved validation practices are essential for scales measuring psychosis proneness. Key aspects, such as cross-cultural validity and long-term stability, remain understudied despite their critical role in ensuring reliable assessments. Content validity remains an issue, as many scales were developed without proper evaluation using qualitative methods, which should be an essential part of the process. Strengthening these areas would enhance the accuracy and applicability of psychosis proneness measures.