Addiction is caused, in part, by powerful and long-lasting memories of the drug experience and relapse caused by exposure to cues associated with these memories and is a major problem in the treatment process. These memories are a result of information sharing between the prefrontal cortex and the dopamine reward system. When something is found to be efficient and effective in dealing with stressors and maintaining homeostasis it is stored for later reference.
For example, a decrease in temperature invokes, for most individuals, the desire to add layers of clothing or cover up with a blanket. This desire is the result of long-lasting and powerful memories stored from learned experiences. The individual is not born knowing that this is the desired response to the stress caused by a decrease in core temperature, yet very likely it is their first impulse.
Similarly, alcohol and drug use are stored in this same way. The prefrontal cortex memorizes the response of the dopamine reward system to the use of the chemical and relates the fact that this is increased from many other stimulants. i.e. it creates greater pleasure than food, fun, family and other forms of recreation; it decreases anxiety; it is effective in acute response to stressors.
This is very important to understand because even after an individual recovers from withdrawal associated with the chemical dependency and physiological adaptations return to normal there is still the presence of these powerful memories to increase the chance of relapse.
Dopamine tells the brain it wants the chemical, Glutamate tells the brain it really likes the chemical, the pleasure center of the brain incites the cue to take action, and the only line of defense is the pre-frontal cortex which is not functioning properly in the alcoholic or addict. This sets the stage for a very difficult journey into sobriety.
Furthermore, a change in the hedonic set point affects an individual’s feeling of wellbeing and euphoria and ability to deal with stress and negative emotions. This change can create a difficult scenario at the early stages of treatment, though this is necessary for the set point to return to natural levels.