Addictive substances can cause a rush of intense pleasure and have substantial effects on the brain. These intoxicated feelings create euphoria and fill the brain with rewarding feelings, activating a release of dopamine, a brain neurotransmitter tied to feeling pleasure. The National Institute of Health’s research has revealed brain imaging studies in humans that show activation of dopamine during alcohol and other substance use, including nicotine. Dopamine is a critical regulator of learning, motivation, energy, attention, and time, which allows an influential reinforcement association with substance consumption and happiness. As time passes with continuous substance use, addiction will be more challenging to put a stop to because natural rewarding behaviors become less satisfying.

Addiction and the Brain

Substance abuse changes brain structure and function, beginning with recognizing pleasure and ending with a tendency for impulsive behavior to regain that pleasure. All addictive substances cause a particularly potent release of dopamine in the nucleus accumbens, the region known as the brain’s pleasure center. According to Harvard Health, addictive drugs can release two to ten times the dopamine amount that natural rewards do. They cut a corner straight to the brain’s “reward circuit,” known as the basal ganglia brain region, by overloading the pleasure center with dopamine. This shortcut plays a significant role in the addiction cycle by trumping the brain’s pleasure and reward system.
Addiction to a substance affects the entire human brain, but certain brain regions play an especially important role in addiction. After substance use rewards the brain, the amygdala brain region stores positive associations of pleasure with that substance to help create a conditioned response—these acquired responses from the brain aid in creating a craving. Continuous use of an addictive substance causes the brain’s prefrontal cortex’s involvement, controlling impulses and stimulating habits by the motivation of the rewarding stimulus that started the addiction cycle.

The Addiction Cycle

Addiction is a repetitive cycle with three stages associated directly with drug use in three brain regions, the basal ganglia, the extended amygdala, and the prefrontal cortex. With effective addiction treatment, the addiction cycle stops at the last stage. In cognitive behavioral therapy, successful management of the executive function, the impulsive control in cognitive behavior, controls your ability to make the right choices not to use a substance when urged or triggered, is addressed.
The three stages of addiction are:

Binge / Intoxication:

This stage significantly involves the basal ganglia, the brain’s “habit circuitry,” because along with dopamine activation, it plays a crucial role in producing rewarding feelings that substance use creates.

Withdrawal / Negative Affect:

During this stage, there is a decrease in the brain’s reward system function. Through withdrawal, which includes negative emotions, the extended amygdala activates the brain’s stress systems.

Preoccupation / Anticipation:

This stage of addiction engages the prefrontal cortex part of the brain, characterized by an interruption of the executive function. The prefrontal cortex region controls the executive function, the capacity to organize thoughts, prioritize, manage time, and regulate one’s actions and emotions.