A gripping investigation into one of the strangest frontiers of human behaviour: how physical and psychological symptoms can spread socially – like viruses.

From the dancing plagues of medieval Europe to the Pokémon episode that hospitalised hundreds of children, social contagion has shaped collective health and hysteria for centuries and across continents. Today, platforms like TikTok and YouTube are driving a new wave – from functional tics to dissociative identities – with symptoms that mimic those of others and spread at startling speed.

Drawing on history, neurology, psychology and culture, social scientist Matilda Gosling shows how our brains and bodies absorb the emotional currents around us. Distress finds new forms of expression in each era: shell shock in the First World War, the recovered memory epidemic of the 1980s, and our modern contagions of identity, pain and fatigue.

Passing through medieval towns, Victorian sanitoriums, modern therapy rooms and the labyrinthine connections of social media, Gosling examines the pull of fear, suggestion and belonging through a vivid cast of spies, witches, influencers and quack practitioners.

THE INFECTIOUS MIND reveals why symptoms spread, why some become epidemics, and how we can protect ourselves in an age of mass connectedness.