Screening for psychotic experiences: Social desirability biases in a non-clinical sample

Aim: Subthreshold psychotic experiences are common in the population and may be clinically significant. Reporting of psychotic experiences through self-report screens may be subject to threats to validity, including social desirability biases. This study examines the influence of social desirability on the reporting of psychotic experiences. Methods: College students (n=686) completed a psychosis screen and the Marlowe-Crowne social desirability scale as part of a self-report survey battery. Associations between psychosis and social desirability were tested using logistic regression models. Results: With the exception of auditory hallucinations, all other measures of psychotic experiences were subject to social desirability biases. Respondents who gave more socially desirable answers were less likely to report psychotic experiences. Conclusions: Respondent's tendency to underreport psychotic experiences should be accounted for when screening for these symptoms clinically. Findings also suggest that population figures based on self-report may underestimate the prevalence of subthreshold delusions but not hallucinations.