Phenomenology and Epidemiology of Obsessive-Compulsive Disorder

Abstract

Abstract The phenomenology and epidemiology of obsessive-compulsive disorder (OCD) are reviewed. Early observers of human behavior identified core OCD phenomenology, the experience of intrusive negative thoughts, and the related repetitive and compulsive behaviors. The evolution of the understanding of OCD is reflected in the psychiatric disorder taxonomy. Both the evolution and how the changes led to the condition’s current conceptualization and definition are evaluated, along with the new obsessive-compulsive and related disorders category. Comorbidity is the rule, not the exception, with OCD. We summarize which conditions co-occur with OCD and how often comorbidity happens. OCD epidemiology is reviewed including the condition’s prevalence, age at onset, and the significant associated disability and high levels of suicidality. OCD heterogeneity is seen in the many types of obsessions and compulsion symptoms observed, the variability in the age of onset, and the different comorbid conditions and the frequency of their comorbidity. Significant heterogeneity across multiple domains is a continuing challenge to the clinician attempting to identify or treat OCD, and to researchers working to better understand the disorder. Significant gains have been made in understanding OCD, but many challenges remain.