Reviewed in this chapter are the research and theory concerning conditions that have in common deficits in impulse control, or disinhibitory psychopathology. Emphasized in particular are the substance use disorders and pathological gambling. Disorders of impulse control are prevalent in all societies and place high costs on the affected individuals, as well as their friends, family members, and often the rest of society. Because they often co‐occur within the same individuals, it is useful clinically and conceptually to understand their psychopathology from a common theoretical perspective. For each of the specific variants of disinhibitory psychopathology, there appears to be multiple etiological mechanisms that convey risk for their development. We have termed these mechanisms positive affect regulation, negative affect regulation, pharmacological vulnerability (in the case of substance use disorders), and deviance proneness. It seems likely that attention to these underlying mechanisms will permit a refinement of diagnosis and provide starting points for new approaches to prevention and treatment. Considered as well are pathologies and etiologies recognized within the research and clinical literature to be specific to individual substance use and pathological gambling disorders.