Less than two hundred years ago, schizophrenia emerged from a tangle of mental disorders known simply as madness. Yet its diagnosis remains shrouded in ambiguity. Only now is the Diagnostics and Statistical Manual of Mental Disorders, psychiatrists’ primary guidebook, shedding the outdated, nineteenth-century descriptions that have characterized schizophrenia to this day. "There is substantial dissatisfaction with schizophrenia treated as a disease entity, it's symptoms are like a fever—something is wrong but we don't know what," says William Carpenter, a psychiatrist at the University of Maryland and chair of the manual’s Psychotic Disorder Workgroup. Psychiatrists may discover that this disorder is not a single syndrome after all but a bundle of overlapping conditions.