Addiction: substances, behaviour and loss of control

From frequency to control

Addiction is not established by one episode, hours spent, or another person’s disapproval. Assessment asks whether use repeatedly exceeds intentions, attempts to reduce it fail, and continued use displaces responsibilities or health. Amount matters for risk, but its meaning depends on the substance, route, and person. Alcohol use disorder also varies in severity; it is not a category for everyone who drinks.

Imagine two adults who report weekend drinking. One can follow an agreed plan; the other repeatedly misses work, drinks before driving, and cannot reduce consumption. The informative differences concern control and consequences, not whether either person appears cheerful. A single dangerous episode warrants attention without proving a continuing disorder. Describing what happened creates a better basis for discussion than attributing the behavior to a defective character. (NIAAA: Understanding Alcohol Use Disorder)

How reward learning changes priorities

Neurons communicate through transmitters, receptors, and changing connections. Some substances alter the strength or duration of those signals, strongly reinforcing actions associated with consumption. Dopamine is not a direct happiness meter. It participates in learning which cues deserve attention and which actions predict a reward. A person may therefore experience strong wanting even when consumption brings little enjoyment.

Consider a journey home that passes a former purchase location. The route, time, and emotional state can become predictive cues that provoke craving before any deliberate purchase decision. Asking for a correct choice only at the final moment overlooks this earlier learning. Changing the route, arranging contact with a supporter, and scheduling another meaningful activity address different parts of the sequence. These are not magical substitutes. They distribute support across a difficult decision instead of expecting one moment of willpower to carry everything. (NIDA: Drugs and the Brain)

Tolerance, withdrawal, and negative reinforcement

Tolerance means that repeated exposure reduces some effects of the same amount. Physical dependence means adaptation that can produce withdrawal when exposure falls or stops. Both can occur alongside addiction, but neither alone defines it. Physical dependence can arise during appropriate medical treatment; impaired control and harmful behavior still require separate assessment. Tolerance also develops unevenly across effects, so feeling less intoxicated does not establish protection from injury.

With continuing use, obtaining pleasure may become less important than briefly relieving anxiety, sleeplessness, or distress. Repetition strengthened by removing an unpleasant state is called negative reinforcement; negative does not mean punishment. This cycle explains why stopping can initially become harder rather than immediately comfortable. Abrupt cessation after prolonged heavy drinking can cause dangerous withdrawal and requires medical assessment. A symptom checklist cannot safely determine medication choice, dosage, or a home withdrawal plan. (NIAAA: Understanding Alcohol Use Disorder)

Behavioral addiction and its boundaries

Problems involving gambling or gaming show that impaired control need not depend on ingesting a chemical. This does not make every repetitive activity an addiction. WHO’s description of gaming disorder emphasizes impaired control, increasing priority, persistence despite consequences, and substantial functional impairment, generally observed over an extended period. Concentrated gaming during a holiday, professional practice, or an absorbing interest is not diagnosed by duration alone.

Context matters. An adolescent excluded at school may find most friendships online. Removing a device does not explain or resolve that situation, although the background does not erase genuine disruption of sleep or attendance. Assessment separates precipitating causes, maintaining factors, and consequences while considering the person’s own goals. Gaming criteria cannot simply be transferred to every example of reading, shopping, or phone use. Unsupported claims of brain damage add fear without improving this distinction. (WHO: Gaming disorder)

Why treatment needs several entry points

Treatment can address substance effects, craving, coping strategies, and practical difficulties at the same time. Medicines for particular substance use disorders and evidence-based behavioral interventions have different indications. Peer and family support may sustain engagement but cannot replace every medical component. Clearing a substance from the body alone usually does not change the learning and circumstances that sustain repeated use. Coexisting mental disorders, pain, housing, and safety may all affect the plan.

For example, someone who reduces use may still face intense craving alone after each night shift. A follow-up visit can examine whether treatment is adequate, whether contact is available at that time, and whether sleep problems are addressed. This analysis neither assigns all responsibility to the environment nor reduces recovery to determination. Options differ for adults, adolescents, pregnancy, and coexisting illness, and require qualified professional guidance and continuing review. (NIDA: Treatment and Recovery)

Evaluate the trajectory of recovery

Recovery may involve safer behavior, continued treatment, better relationships, and renewed participation in education or work. A return to use should prompt risk assessment and reconsideration of the plan; it does not show that change is impossible. It should not be portrayed as harmless or inevitable either. After abstinence reduces tolerance, a previously used amount may cause severe overdose. Unresponsiveness, abnormal breathing, or other acute danger requires local emergency help.

For reasoning, reconstruct a sequence: reduced sleep, increased stress, an old cue, stronger craving, use, and consequences. Ask which links are supported before choosing what to change. The final behavior alone cannot establish every preceding cause. Defining progress through sustainable health and functioning makes improvement observable. Supporters can express concern, assist access to care, and maintain their own safety boundaries. Shame and covert monitoring are poor substitutes for a trustworthy working relationship. (NIDA: Treatment and Recovery)

Bilingual terms

强化 · Reinforcement

A process that increases the likelihood of repeating behavior.

渴求 · Craving

A strong desire to use a substance or engage in a behavior.

耐受 · Tolerance

Reduced effects of the same amount after repeated exposure.

身体依赖 · Physical dependence

Adaptation that can cause withdrawal when exposure decreases.

负强化 · Negative reinforcement

Strengthening behavior through removal of an unpleasant state.

Sources and further reading

• NIDA: Drugs and the Brain
• NIDA: Treatment and Recovery
• WHO: Gaming disorder
• NIAAA: Understanding Alcohol Use Disorder

Original course source-check record: 9 September 2026. Full Chinese and English sentence-by-sentence language review: 14 September 2026. AI editing and language review are not human clinical review. Linked institutions have not participated in or endorsed this course.