Goal disruption theory (GDT, see Siegel, 2004; 2011; 2013; Siegel et al., 2012), steeped in the theorizing of Tolman (1932, 1959) and Lewin (1932, 1936, 1941), expands upon and unites numerous intellectual advances made in the fields of medicine (Devins, 1994), anthropology (Becker, 1999), communication (Berger & Calabrese, 1975; Burgoon & Hale, 1988), sociology (Lipman-Bluman, 1975), social psychology (Crano & Prislin, 2008; Festinger, 1957; Hogg, 2007, 2009; Higgins, 1989; Wills, 1981), and positive psychology (Csikszentmihalyi, 1990; Fredrickson, 2001). The theoretical framework offers insight into when a goal expectancy violation is most likely to cause goal disruption (i.e., psychological disequilibrium or disharmony), the intensity with which psychological disequilibrium is likely to be experienced, and the adaptive processes that automatically follow. The theory originally stemmed from a dissertation (Siegel, 2004), which used the theorizing of Tolman (1932,1952) and Lewin (1932, 1936, 1941) to demonstrate that an individual's desired end-state, or goal, is related to their willingness to endure harm to achieve this goal (i.e., purposive harm endurance). Siegel (2011), Siegel and colleagues (2012), Lewandowski, Rosenberg, Parks, and Siegel (2011), and Rosenberg, Lewandowski, and Siegel (in press) followed up this initial study by demonstrating that need for goal and purposive harm endurance are related to one another in multiple domains. Rosenberg, Lewandowski, and Siegel (in press) demonstrated that this relationship is nuanced—some goals elicit more need than others, and some goals elicit more purposive harm than others. The first studies of GDT utilized this assumption to demonstrate experimentally that a specific type of goal frustration, an unexpected goal violation, is associated with increased need for goal, purposive harm endurance, and aggression, as well as decreased creativity and ability to think broadly (De Dreu, Nijstad, Baas, 2011; Eisenberger & Rhoades, 2001). Other studies have demonstrated the role of unexpectedness, and why a goal violation leads to differential effects (Amsel, 1958; Amsel & Hancock, 1957; Mendes et al., 2007). GDT is presently being applied to persuasive processes (Rosenberg & Siegel, in preparation) and illicit stimulant use (Lyrintzis & Siegel, under review).