Obsessive-Compulsive Disorder Related Disorders: Hypochondriasis, Hoarding Disorder, Olfactory Reference Disorder, Body Dysmorphic Disorder, Trichotillomania, Excoriation Disorder

The obsessive-compulsive or related disorders are common, occur around the world, and are often severe and challenging to treat. Several are associated with markedly elevated rates of suicidality. Yet, these disorders often go unrecognized in clinical practice. This chapter focuses on the following disorders: hypochondriasis, hoarding disorder (HD), body dysmorphic disorder (BDD), olfactory reference disorder (ORD) (more widely known as olfactory reference syndrome), trichotillomania (hair-pulling disorder) (TTM), and excoriation (skin-picking) disorder (SPD). Several of these disorders were newly added to one or both of the most recent editions of the field’s two major classification manuals, and thus they may be less familiar to readers: olfactory reference disorder (ICD-11 only), hoarding disorder, and excoriation (skin-picking) disorder. This chapter describes the diagnosis, clinical features, epidemiology, etiology, treatment, and other key features of the above-noted obsessive-compulsive or related disorders. It is hoped that this chapter usefully assists clinicians in recognizing and treating these common and often severe yet often overlooked and treatable conditions.