When someone engages in a pleasurable activity like gambling, their brain releases dopamine, a neurotransmitter that processes rewards. Dopamine is what makes these activities feel pleasurable. Psychiatrist Anna Lembke explains that pleasure and pain act on an equilibrium, encouraging limits on the activity in question, no matter how enjoyable. Over time, repeated exposure to pleasure means the brain requires more of that activity—gambling with more money, for example—to receive the same amount of dopamine. Once someone has built up a tolerance, they are susceptible to addiction and, with their equilibrium imbalanced in favor of pain, they will need ever-increasing amounts to experience even a modicum of pleasure—or simply a break from pain.
