Abnormal and normal obsessions: a reconsideration

Contemporary cognitive approaches to obsession assume that the content of clinical obsessions does not differ from non-clinical obsessive intrusions. This assumption goes back to a classic study by Rachman and De Silva [(1978). Abnormal and normal obsessions. Behaviour Research and Therapy, 16, 233-248]. In the present paper, it is argued that Rachman and De Silva did not postulate a complete indifference between clinical and non-clinical obsessions. Study 1 is a simple statistical analysis of data presented by Rachman and De Silva. This analysis suggested that psychologists are able to discriminate clinical and non-clinical obsessions beyond chance level, merely by looking at the content of obsessions. In study 2, a list of 23 clinical and 47 non-clinical obsessions was presented to 11 psychotherapists and 90 psychology undergraduates. Both therapists and students were able to distinguish clinical and non-clinical obsession beyond chance level. It is concluded that some clinical obsessions can be identified as being evidently abnormal, and that additional theory and research is needed to identify the causes of these recognisable obsessions.