Linking ADHD, impulsivity, and drug abuse: a neuropsychological perspective

In this chapter, we consider the relevance of impulsivity as both a psychological construct and endophenotype underlying attention-deficit/hyperactivity disorder (ADHD) and drug addiction. The case for executive dysfunction in ADHD and drug addiction is critically reviewed in the context of dissociable cognitive control processes mediated by the dorsolateral prefrontal cortex (DLPFC), the orbital and ventral medial prefrontal cortex (VMPFC). We argue that such neuroanatomical divisions within the prefrontal cortex are likely to account for the multidimensional basis of impulsivity conceptually categorized in terms of "motoric" and "choice" impulsivity. The relevance of this distinction for the etiology of ADHD and drug addiction is integrated within a novel theoretical framework. This scheme embraces animal learning theory to help explain the heterogeneity of impulse control disorders, which are exemplified by ADHD as a vulnerability disorder for drug addiction.