Impulsivity is increasingly recognized as a clinically important feature of many psychiatric disorders and clinical concerns. Although widely regarded as a multifaceted construct, there is little consensus as how to best define impulsivity. As this review will highlight, the term behavior refers to a broad range of behavioral tendencies that is highly variable in both form (topography) and function. Following a review of theory and basic research on impulsivity, a behavioral framework for conceptualizing action is proposed. Within this framework, behaviors are categorized according to their associated functional properties or corresponding skills deficits. Behavioral interventions conceptually tied to these functional formulations of impulsivity are briefly highlighted. CONCEPTUALIZING THE DOMAIN OF IMPULSIVITY: SUGGESTIONS FROM PERSONALITY THEORY AND RESEARCH Impulsivity is not a unitary concept; rather, the label impulsive is often applied to a heterogeneous collection of behaviors that vary considerably in terms of form and function. Some conceptualizations of impulsivity, for example, emphasize the adaptive qualities associated with acts under some circumstances. Dickman (1990; Dickman & Meyer, 1988), for instance, has highlighted a form of impulsivity that is characterized by actions performed with little forethought that result in positive or optimal outcomes (e.g., suddenly breaking and maneuvering a car in order to avoid an object on the road). The ability to respond quickly and skillfully with little deliberation can be adaptive or beneficial in such circumstances. Dickman contrasts this form of impulsivity with a more maladaptive or non-optimal form of impulsivity, whereby actions are frequently carried out with little planning or forethought and have a relatively high likelihood of producing inaccurate, non-optimal, harmful, or aversive outcomes (e.g., engagement in unplanned and risky sexual behavior while intoxicated with a previously unknown partner following a chance meeting). Several different manifestations of impulsivity, both adaptive and maladaptive, have been described in the personality and clinical literatures (e.g., Barrett & Stanford, 1996; Depue & Collins, 1999; Evenden, 1999; Whiteside & Lynam, 2001; Zuckerman, 1996), including: sensation seeking, risk taking, novelty seeking, thrill or excitement seeking, reward seeking, extraversion, venturesomeness, hyperactivity, response perseveration, and need for immediate gratification. Other references to actions suggest the absence of a skill or some other type of deficit: disinhibition, low deliberation/premeditation, deficit response reflection, impatience, low persistence, non-planning, low future orientation, low harm avoidance, low anxiety, poor inhibitory control, poor fear conditioning, low self-control, poor self-regulation, impaired capacity for delay, inability to delay gratification, inability to refrain from acting on urges or impulses, and low persistence. Finally, conceptualizations of impulsivity have also included forms of behavior that are occasioned by other factors, such as urgency for action under conditions of negative affect (Wallace, Bachorowski, & Newman, 1991; Whiteside & Lynam, 2001). These various forms of impulsivity are distinct in terms of topography, function, and associated behavioral skills and their inclusion under the same construct label masks important distinctions in their functions and associated predisposing factors. As will be reviewed shortly, sensation seeking and risk taking are examples of actions that might be primarily maintained by positive reinforcement processes that accompany such behaviors. Conversely, fearlessness or disinhibition might denote behavioral tendencies that appear on the surface, but that actually refer to a general non-reactivity to aversive stimuli or punishment cues that would otherwise inhibit behavior. …