Addiction is a condition marked by compulsive engagement with a substance or behavior despite harmful consequences. The person continues to seek the drug or the activity even when it damages health, relationships, work, and self-respect.

Neurobiologically, addictive drugs hijack the brain’s reward circuitry, particularly the dopamine pathways that normally reinforce survival-related behaviors. Repeated exposure produces tolerance—more of the substance is needed for the same effect—and dependence, so that withdrawal symptoms appear when use stops. Craving can persist long after the body has cleared the drug, driven by conditioned cues and by lasting changes in brain circuitry. Behavioral addictions such as gambling activate overlapping systems.

Not everyone who uses a substance becomes addicted. Genetic vulnerability, early stress, mental health conditions, and social environment all influence risk. Treatment approaches include medication to ease withdrawal or block drug effects, cognitive-behavioral therapy to change habits and coping strategies, and mutual-help groups that provide structure and accountability. Relapse is common and is better viewed as part of the chronic course than as moral failure.

Addiction narrows life until the substance or behavior becomes the organizing principle. Recovery is the slow widening of that life again.