The relation between the dopaminergic system, drug addiction, and brain structures related to reward behaviors and decision-making

Drug addiction is a serious global health problem that affects the brain, behavior, and decision-making of people, leading to an inability to control drug use.The pharmacological effects of drugs, experienced as a reward, are driven by a variety of genetic, environmental, developmental, and psychosocial factors and are mainly regulated by the dopaminergic system in the reward circuit, with the ventral tegmental area and nucleus accumbens being the most important.Dopamine, the main neurotransmitter, is responsible for regulating physiological functions, including reward-related behaviors.When substance abuse occurs, dopamine is released in greater quantities, forming a connection between the substance and the feeling of reward, thus creating a desire for more pleasurable effects.Dopamine receptors also play a direct role in generating intracellular signals related to pleasure and rewards.Drugs with addictive potential can downregulate the activity and expression of dopamine receptors in the brain.This review focuses on understanding the role of dopamine, the dopaminergic system, and brain structures related to rewards and associated behaviors in drug addiction.