Psychosis is often thought of as existing on a continuum with clinically diagnosed patients representing the pathological extreme. Subclinical psychosis-like experiences and schizotypal signs, including persecutory beliefs and hallucinations, are not uncommon in the general population. Both stress and levels of caffeine consumption have been demonstrated to exacerbate psychotic phenomena. In this study, reported caffeine consumption, perceived stress, and predisposition to hallucinate were measured in 129 healthy volunteers. The White Christmas Task (WCT) and the Deese–Roediger–McDermott (DRM) paradigm were used as measures of false perception and memory. Reported caffeine consumption was found to be a predictor of liberal bias on the WCT, and stress was found to be a predictor of liberal bias and reduced discriminability on the DRM. Finally, participants high on schizotypy were found to be insensitive to emotional valence on the DRM. It was theorized that these findings may be due to the assignment of undue adaptive importance resulting from elevated dopamine transmission in the striatum.
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