Abstract

This article historicizes a single stage in how the contemporary obsessive–compulsive disorder (OCD) category was built. Starting from the position that the two central components which make up OCD are ‘obsessions’ and ‘compulsions’, it illustrates how these concepts were taken apart by a small group of clinical psychologists working at the Institute of Psychiatry and the Maudsley psychiatric hospital in south London in the early 1970s, and why compulsions were investigated whilst obsessions were ignored. The decision to distinguish the previously undifferentiated symptoms is attributed to the commitment amongst psychologists at the Maudsley, most notably Stanley Rachman, to an empirical conception of science which emphasized observability. Two aspects of this are discussed. First, compulsions were deemed ‘visible’ through their correspondence with animal behaviour. Second, the symptom was seen as open to an experimental modification procedure which privileged visible outcomes. Ultimately, the article concludes that the historical division between ‘obsessions’ and ‘compulsions’, and the extensive investigation of the latter, has had substantial implications for the development of OCD as a category centred on visible behaviours and treated through behavioural means.