It is a common misconception that dopamine is only released when pleasurable or positive things occur to people. In fact, dopamine has been found to be released in times of pain as well. This might partially explain the self sabotaging behavior that some people face.
According to the reigning “reward prediction error hypothesis,” these dopamine neurons are activated and produce dopamine when an action is more rewarding than we expect, but they remain at baseline activity when the reward matches our expectations and show depressed activity when we receive less reward than predicted.
Dopamine changes neural circuits and trains the brain – for better or worse – to pursue the pleasurable and avoid the unpleasurable.