Introduction

Over the course of their lives, many people have indistinct and transitory obsessive episodes or subclinical symptoms. It is not unusual for people to return home to make sure they closed the front door correctly or to feel contaminated after using a public bathroom and to wash their hands more thoroughly than they would normally. Aggressive, blasphemous sexually perverse thoughts, or thoughts in any case believed to be morally unacceptable can intrude into anybody’s mind and it sometimes happens that we make a concerted effort to neutralise them. Guilt and horror, the latter an emotion that mixes disgust and fear, play a fundamental role in the famous case of the Rat Man described by S. Freud. The role of morality, therefore, has been widely recognised in the pre-scientific and scientific history of obsessive-compulsive disorder.