This study traces key developments in theatre’s engagement with mental health since the 1970s. It introduces and applies the concept of the ‘mental health play’ as accurate and timely in addressing the way mental distress and mental illness have been brought to the stage. The study argues that the theatre is a central calibrator for reflecting developments and tensions in, as well as attitudes towards, mental health care, and thus opens up a domain that still has stereotypes and myths attached to it. Theatre’s representations of mental distress inform and shape cultural production and vice versa. Mental health plays are central in encouraging and fostering conversations about mental health, and they thus intervene in ongoing debates. Due to its interdisciplinary approach, this study contributes to and extends existing research in multiple fields, including theatre and science, performance studies, and the medical humanities.