This article opens with a retelling of colonial accounts of the ‘mania of 1911’, which took place in the Kamba region of Kenya Colony. The story of this ‘psychic epidemic’ and others like it would be recounted over the years as evidence depicting the predisposition of Africans to episodic mass hysteria. This use of medical and psychological language in primarily non-medical contexts serves to highlight the intellectual and political roles psychiatric ideas played in colonial governance. The salience of such ideas was often apparent in the face of increasing social tension, charismatic leadership and a proliferation of East African prophetic movements. This article addresses the attempts by the colonial authorities to understand or characterize, in psychological terms, a progression of African ‘rebellious types’ in society that often took the form of prophets and visionaries, but were diagnosed as epileptic, neurotic or suffering from ‘religious mania’.