The dopamine motive system: implications for drug and food addiction

The motivation to eat, like the motivation to take addictive drugs, activates the forebrain dopamine systems.Excessive activation of this system strengthens the specific habits that precede the activation, sensitizing the animal's responsiveness to the specific conditions that elicit those habits.At the same time, overactivation of the dopamine system downregulates the dopamine receptors, leaving the subject less interested in other activities.The repeated intake of high-impact foods or addictive drugs thus makes food consumption or drug taking more habitual and decreases the importance of stimuli calling for alternatives.Repeated drug use erodes the function of brain networks necessary for self-regulation, thereby facilitating impulsive, inflexible and compulsive actions.