DIFFERENT PEOPLE, DIFFERENT STORIES

Neuropsychiatry, perhaps more than any other medical field, has to contend with the complexities of individual experience even as it searches for general explanations. Medical research is meant to identify categories of disorder that allow clinicians to look past the idiosyncratic aspects of a patient’s illness to the underlying mechanisms of the disease. But in the neuropsychiatric clinic, biographical factors—such as trauma, family dynamics, or social determinants of health—are often stubbornly tangled up with these mechanisms. Only in quite rare cases, like that of the lone gene that causes Huntington’s disease or the spirochete that causes syphilis, is a single grim biological fact to blame for a mental pathology. Even so, disciplines like neurology and psychiatry require taxonomies of disease.

The 18th-century naturalist Charles Bonnet thought that for intelligences higher than ours—presumably God and his angels—classification was