Contamination concerns and checking remain two of the most prevalent forms of presentation in OCD, reported by 25–50% of sufferers, with checking the most common compulsion. Since they cover a broad spectrum of concerns and complexity, the assessment and treatment of contamination and checking carries its own challenges for the therapist. This chapter explores the nature of contamination and checking concerns and provides an overview of recent research. Practical advice and guidance will guide the therapist from initial assessment to formulation and the development of an effective treatment protocol. The prevalence of covert safety-seeking behaviors such as rumination is discussed as a frequent obstacle in treatment. It advocates a move away from graded hierarchies for exposure and considers what effective exposure should consist of, encouraging the use of creativity and playfulness. A range of both common and less common presentations is used to illustrate key concepts.

Cognitive behavior therapy (CBT) is the treatment of choice for people with body dysmorphic disorder (BDD). The first part of the chapter describes the clinical features and processes of BDD, and introduces an updated CBT model of the self as an aesthetic object that evolves around the notion that people with BDD experience distressing mental imagery of their disliked features, maintained by self-focused attention and safety-seeking behaviors. In the second part of the chapter, we present an updated assessment and treatment protocol to BDD. We use case material to illustrate how to engage clients and socialize them into a psychological way of working to overcome their appearance concerns. We illustrate assessment and formulation, how to set up effective behavioral experiments, how to conduct mirror retraining, imagery rescripting, and compassion-focused techniques. BDD screening and diagnostic measures are also presented.