In the 1950s, researchers stumbled upon a new class of drugs that provided relief for those suffering from schizophrenia. These drugs were known as antipsychotics and, as the name suggests, they reduced symptoms like hallucinations and delusions — primarily by reducing the levels of dopamine in the brain. This led clinicians and scientists to argue that dopamine was linked to the experiences of psychotic symptoms, and a concerted research effort ensued, seeking to solve the puzzle of why excess dopamine might produce hallucinations. Although it was later shown that increasing dopamine could produce hallucinations, establishing a consistent link between them,...