THE FUSE

In 1877, French psychiatrists Charles Lasègue and Jules Falret introduced the concept of folie à deux, a condition in which two people share a delusional belief system. The French term translates loosely to "madness for two" and eventually became known as shared psychotic disorder. Although it no longer exists as a standalone diagnosis in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the concept remains relevant to understanding how two people can reinforce a distorted perception of reality.