[Measuring psychosis-like symptoms and their relationship with caffeine consumption in healthy adult population].

INTRODUCTION: Our study is based on the concept that mental disorders - including psychotic symptoms - should be treated as dimensions/continuums rather than categories; an approach supported in the DSM-5 as well. Consequently, the measurement of certain symptoms of psychosis (e.g. hallucinations, persecutory ideation) may also be important in the normal population. We have performed the Hungarian adaptation of two questionnaires - the Persecutory Ideation Questionnaire and the Launay-Slade Hallucination Scale - in the current study and we also examined the relationship of the consumption of various caffeinated beverages, caffeine use disorder, the tendency to hallucinations and persecutory ideations.

METHOD: 2259 adults (70.5% male, mean age = 34 years [standard deviation = 9.3]) participated in our cross-sectional online survey, completing the Persecutory Ideation Questionnaire, the Launay-Slade Hallucination Scale, the Caffeine Use Disorder Questionnaire and questions about caffeine consumption habits.

RESULTS: The Persecutory Ideation Questionnaire had a one-factor structure and its internal consistency was excellent. In the exploratory factor analysis of the Launay-Slade Hallucination Scale two factors emerged ("Vivid mental events" and "Clinical hallucinations"), but other factor solutions cannot be completely excluded. The moderate correlation between the two questionnaires indicates an appropriate divergent validity. There were no correlations between psychotic symptoms and caffeine, coffee, tea and cola consumption. A slightly increased level of persecutory ideation in the daily energy drink consumers was observed compared to non-daily consumers. The magnitude of caffeine use disorder symptoms had a moderate positive correlation with psychotic symptoms.

CONCLUSION: Both the Persecutory Ideation Questionnaire and the Launay-Slade Hallucination Scale are appropriate tools for measuring psychotic experiences in the healthy adult population. Further research may aim to test the questionnaires in a clinical population.