Compulsivity is the defining feature of various psychiatric disorders including Obsessive Compulsive Related Disorders (OCRDs), and other compulsive, impulsive, and addictive disorders. These disorders are disabling, chronic conditions with an early onset and high rates of comorbidity, misdiagnoses, and delay in treatment onset. Disorders of compulsivity are responsible for considerable socioeconomic burden to society. We review the costs and impacts of compulsivity. In order to facilitate earlier diagnosis and targeted treatments, we examine the overlapping mechanisms that underlie compulsivity. We reconceptualize psychiatric disorders based on core features of compulsivity, highlight challenges in harmonizing research in children and adults, describe newer research methodologies, and point to future directions that can impact the costs and impact of disorders of compulsivity.