Despite relatively high prevalence rates and significant morbidity and mortality associated with pathological gambling (PG), our understanding of the neurobiological basis of PG lags in comparison to that for other psychiatric illnesses of comparable magnitude. An improved understanding of the neurobiology of PG would facilitate targeted investigations into more effective treatments. Emerging data suggest shared neurobiological features determine in part pathological gambling and substance use disorders. These findings both challenge current conceptualizations of addictions and provide a substantial basis of knowledge on which to design investigations into the understanding and treatment of pathological gambling. The findings that substance use disorders and the behavioral "addiction" of PG share common causative features raise the question as to what extent other compulsive disorders (eg, compulsive shopping, compulsive sexual behaviors, compulsive computer use) might be biologically related.