Current Classification of Impulse Control Disorders: Neurocognitive and Behavioral Models of Impulsivity and the Role of Personality

Impulse control disorders (ICDs) are common disabling disorders that have impulsive behavior as a core feature. They emerge early in life and run a chronic lifelong course. They are assumed to lie at the severest end of a continuum of impulsivity that connects normal with pathological states. People with ICDs experience a drive to undertake repetitive acts. Although the consequences are damaging, performance of the impulsive act may be experienced as rewarding, or alternatively may relieve distress, implicating dysfunction of the neural circuitry involved in reward processing and/or behavioral inhibition. Clinical data are increasingly pointing toward an etiological association between some ICDs, such as pathological gambling and addiction, and others, such as trichotillomania and compulsive disorders. Comorbidity with other psychiatric disorders is also common, and hints at overlapping psychobiological processes across several diagnostic groups. The results of neurocognitive studies suggest that impulsivity is multidimensional and comprises dissociable cognitive and behavioral indices governed by separate underlying neural mechanisms. For example, trichotillomania may primarily involve motor impulsivity, whereas problem gambling may involve reward impulsivity and reflection impulsivity. Exploring neurocognitive changes in individuals with ICDs and other mental disorders characterized by poor impulse control, and among their family members, may help to elucidate the underpinning neurocircuitry and clarify their nosological status.