The Reward System

Figure 1 depicts the body’s reaction to a positive experience – the normal reward, or pleasure, system. On the left are the body’s needs, or drives: Hunger, sex, thirst, and friendship. When these drives are satisfied, a signal transmits to the monitoring cells of the brain. These monitoring cells release a chemical that signals reward, resulting in a feeling of well-being.

Drug and Alcohol Effects on the Brain Reward System

Figure 2 shows the effects that alcohol and drugs have on the brain reward system. Addictive substances produce an artificial feeling of pleasure by chemically mimicking normal brain messenger chemicals. These chemicals produce positive feelings in response to signals from the brain.
Figure 3 shows how the first association with alcohol or drugs is locked in the subconscious memory. The subconscious learns through immediate association, remembers that initial ‘‘high” and actually forces the individual to want to recapture it. A tolerance develops to the euphoric effects, and higher and higher doses of the addictive substance are needed to get its pleasurable effects.