Although many of the people Earley profiles experience episodes of psychosis, psychosis is not in and of itself a diagnosis. Rather, it describes the state of struggling to differentiate between what is real and what isn’t; common features include delusions (beliefs that do not correspond to reality) and hallucinations (sensory perceptions, often auditory or visual, that do not correspond to reality), though both delusions and hallucinations can occur independent of psychosis. Psychosis or psychosis-like states can result from various causes, including drug use, neurodegenerative disorders, and certain nutritional deficiencies. However, laypeople are likely most familiar with psychosis in connection with mental illness—particularly schizophrenia and bipolar disorder.

Schizophrenia is a thought disorder that commonly involves delusions (often of being threatened in some way), hallucinations, and changes in social behavior (e.g., withdrawal from relationships, decreased ability to express or interpret emotions, etc.). It most commonly emerges in early adulthood, although the symptoms are likely to wax and wane throughout an individual’s life. Its exact cause is unknown, but it likely stems from a combination of genetic and environmental factors. Schizophrenia is associated with various changes in brain structure and activity, particularly in connection to the neurotransmitter dopamine.