In early modern Scotland, several visionaries experienced vivid relationships with spirits. This paper analyses their experiences historically, with the aid of modern scholarship in medicine, psychology and social science. Most of the visionaries were women. Most of their spirit-guides were fairies or ghosts. There could be traumas in forming or maintaining the relationship, and visionaries often experienced spirit-guides as powerful, capricious and demanding. It is argued that some visionaries experienced psychotic conditions, including psychosomatic injuries, sleepwalking, mutism and catatonia. Further conditions related to visionary experience were not necessarily pathological, notably fantasy-proneness and hallucinations. Imaginary companions and parasocial relationships are discussed, as are normality, abnormality and coping strategies. There are concluding reflections on links between culture and biology.