Hallucinations and delusions can be symptoms of psychiatric illness, but more often—though less commonly known—are actually part of a healthy range of experiences found throughout the general population. The studies in this Special Collection paint a picture of the wide range of hallucinatory and delusional experiences across diverse populations, as well as comparative perspectives between clinical and non-clinical samples. In this editorial, I make three related points that are exemplified in the articles published here. First, that hallucinations and delusions are part of a normal distribution of human diversity; their mere presence does not indicate psychosis or psychiatric illness. Second, that the ubiquity of hallucinatory and delusional experiences across clinical and non-clinical populations suggests common cognitive and neural mechanisms. Finally, despite these commonalities, it is important to understand the difference between psychiatric symptoms and healthy experience. In summary, I conclude that it is important to investigate both common mechanisms and distinguishing factors to comprehensively elucidate these oft-misunderstood experiences. This Special Collection provides a showcase of the cutting-edge research that encompasses these objectives.
