addiction
Meaning of addiction: Compulsion is the defining feature, not the amount used, which is why a person can be dependent on a medicine without being addicted to it.
Definition of addiction
Addiction is a pattern of compulsive use in which seeking and taking a substance crowds out other activities and continues despite clear harm. It develops with repeated exposure and involves lasting changes in the brain circuits governing reward, motivation and self-control. Clinicians usually record it as a substance use disorder, which is the diagnostic term.
How is it different from dependence and tolerance?
| Term | What it describes |
|---|---|
| Tolerance | The same amount produces less effect, so more is needed for the same result |
| Physical dependence | The body has adapted, so stopping produces withdrawal symptoms |
| Withdrawal | The symptoms that appear when a substance is stopped or reduced |
| Addiction | Compulsive seeking and use despite harm, whether or not the body has adapted |
The first three are physiological and expected. A person taking an opioid for cancer pain, or a beta blocker for the heart, develops tolerance and physical dependence without any compulsive pattern, and stopping abruptly causes withdrawal in someone who was never addicted. Addiction adds behavior to physiology, and it is the behavior that defines it.
What happens in the brain?
Substances that lead to addiction all increase dopamine signaling in the reward circuit, a pathway that normally reinforces eating, drinking and company. The surge is larger and more reliable than anything ordinary experience produces, and the circuit learns from it, attaching strong value to the cues that predicted the substance: a place, a time of day, a person, a smell. With repetition the reward itself diminishes while the wanting strengthens, so use continues for relief rather than pleasure, and the same psychological conditioning leaves cues able to trigger craving long after the substance has gone. Meanwhile the frontal regions that weigh consequences and hold back impulses work less effectively. That combination, strengthened craving and weakened restraint, is why relapse can follow years of abstinence.
Is addiction only about substances?
Mostly, but not entirely. Alcohol, opioids, stimulants, nicotine, cannabis and sedatives are the substances involved, and what was long called alcohol dependence is the oldest recognized form. Gambling disorder is the one behavioral condition classified alongside the substance use disorders, because the same reward circuits and the same pattern of escalation, craving and continued involvement despite loss are present. Other repetitive behaviors are called addictive in everyday speech, and internet gaming is listed as a condition needing further study, but they are not established diagnoses. The distinction matters, because a diagnostic label carries consequences that a figure of speech does not.
Used in a sentence
The patient was referred to a specialist for evaluation of suspected opioid addiction.
Good to know
Addiction, a behavioral pattern of compulsive use, is distinct from physical dependence, in which the body adapts to a substance and produces withdrawal if it is stopped, since dependence can occur without the compulsive pattern that defines addiction.
Word origin
Where “addiction” comes from
From Latin addictio, a formal binding over or surrender, from addicere, formed from ad-, to, and dicere, to declare.