Goal disruption theory (GDT) hypothesizes that negative goal expectancy violations have the potential to cause psychological disequilibrium (i.e., a goal disruption) depending on numerous factors, such as the importance of the violated goal.  When disruption occurs, adaptive processes are triggered with the goal of returning to equilibrium.  The current set of studies empirically supports these components of GDT and applies the theory to nonmedical prescription stimulant use. In three different studies, consistent support was found for the notion that purposive harm endurance is an adaptive response to receiving an unexpectedly poor grade on an important test (i.e., a negative violation).  This occurs when the goal is important (Study 1), was found to mediate the relationship between the violation and engaging in stimulant use (Study 2), and occurs through the process of psychological disequilibrium (Study 3).