A Basic Primer on the Human Brain
The brain is made up of many parts with interconnected circuits that all work together as a team. Different brain circuits are responsible for performing specific functions. Networks of neurons send signals back and forth to each other and among different parts of the brain, the spinal cord, and nerves in the rest of the body.
The Cycle of Addiction
Nearly all substances directly or indirectly impact the brain’s reward system by flooding the circuit with dopamine. Dopamine is a type of neurotransmitter, something that is made by your body to send messages between nerve cells. These messages can be activated by a healthy, pleasurable experience. Bursts of dopamine signals can cause changes in neural connectivity that signal to your brain to repeat that activity, the one that is causing pleasure. Without thinking about it, a habit is formed.
Surges of dopamine in the brain’s reward circuit cause repetition of behavior. As a person continues to use substances, the brain adapts by reducing the ability of cells in the reward circuit to respond to it. A person using substances might take more of the drug to obtain the high they felt when first taking the drug. After long-term use, functions such as learning, judgment, decision-making, stress, memory, and behavior are impacted through these changes to the reward circuit.
Cues in a person’s daily routine or environment that have become linked with substance use can trigger uncontrollable cravings whenever the person is exposed to these cues, even if the substance itself is not available. This reflex can last a long time, even years after one’s last use of that substance. This continues to cause cravings and can even begin to cue them involuntarily.
NIDA. “Understanding Drug Use and Addiction DrugFacts.” National Institute on Drug Abuse, 6 Jun. 2018, https://nida.nih.gov/publications/drugfacts/understanding-drug-use-addiction.