ABSTRACT This article explores the relationship between wartime captivity and the production of medical knowledge through the phenomenon of ‘barbed wire disease’. This was a term used by First World War POWs and internees themselves to describe symptoms of depression and related neurological disorders. The Swiss surgeon Adolf Lukas Vischer borrowed it for the title of a book he wrote in 1918 suggesting that the spatial and temporal peculiarities of camp life made prolonged captivity in such an environment inhumane and a threat to future societal stability. The article argues that Vischer’s findings should be seen through the lens of historical time. His observations led him to draw attention to the contemporaneous plight of previously highly mobile and self-reliant migrants across the world now living for an unknown duration within the confines of the barbed wire. Yet equally, the article makes the case for thinking in a transhistorical way about the (often under-appreciated) mutual inter-dependence of social knowledge and medical thinking, especially in times of large-scale displacement. The shadow of the past, it will be suggested, continues to shape approaches to the mental health problems faced by people living in atypical temporal and spatial settings today, including those experiencing the symptoms of Long Covid and those held in immigration detention.