Arguably, clubbers taking ecstasy and dancing until they die of hyperthermia are doing exactly this.

From my experience, dopamine agonism can significantly improve my ability to exert willpower. That does not mean it allows for unbounded enhancement, however: psychoactives merely allow for intertemporal transfer of particular cognitive functions, due to downregulation of receptor sites. However, just like credit allows for intertemporal transfer of purchasing power, you can vastly increase your utility by shifting your cognitive function to optimal times.