Addiction is a chronic, relapsing pattern of behaviour involving compulsive use of a substance or engagement in a behaviour despite harmful consequences. ICD-11 has separate categories for substance dependence and disorders due to addictive behaviours (e.g. gambling, gaming).
Substance vs behavioural addiction
- Substance addiction — alcohol, nicotine, illicit drugs, prescription painkillers.
- Behavioural addiction — gambling, gaming, internet/pornography compulsion. Some controversy: not all psychologists agree all behavioural patterns merit "addiction" labels, but ICD-11 explicitly recognises gambling and gaming disorders.
Both involve the same underlying neural reward circuitry (especially the mesolimbic dopamine pathway — ventral tegmental area to nucleus accumbens).
ICD-11 criteria for substance dependence
Three or more of the following over a 12-month period:
- Strong desire or compulsion to take the substance (cravings).
- Impaired control over use (starting, stopping, level).
- Use takes priority over other activities and obligations.
- Tolerance — needing more of the substance to achieve the same effect.
- Withdrawal symptoms when use stops or reduces.
- Continued use despite harmful consequences (health, work, relationships).
- Salience — the substance dominates thoughts and behaviour.
Tolerance and withdrawal — physiological signs
Tolerance develops as the body adapts to repeated exposure: receptors downregulate, requiring higher doses for the same effect. Withdrawal is the constellation of symptoms when the drug is removed — alcohol withdrawal includes tremor, sweating, anxiety; nicotine withdrawal includes irritability and cravings.
Tolerance and withdrawal are key features of physical dependence but not always present in behavioural addictions (gambling shows tolerance — bigger bets — but no biochemical withdrawal).
Impact on the person
- Health — physical (liver, lung, heart), mental (depression, anxiety), risk of overdose.
- Relationships — strain, breakdown of trust, neglect.
- Finances and employment — debt, job loss.
- Legal — driving offences, criminal involvement.
Impact on society
- Healthcare costs (alcohol-related admissions ~£3bn/year UK).
- Productivity loss; benefit costs.
- Crime and policing — much acquisitive crime is drug-related.
- Family and child welfare implications.
Distinguishing addiction from heavy use
Heavy use can be harmful but is not by itself addiction. Addiction requires:
- The compulsive quality (cravings, impaired control).
- Continued use despite consequences — the person can't stop even when wanting to.
- Often tolerance and withdrawal for substance addictions.
Risk factors
Multiple, interacting:
- Genetic vulnerability (P2.PS.6 — Kaij twin studies).
- Family environment — modelling, neglect, abuse.
- Peer influence — see learning theory in P2.PS.6.
- Mental health comorbidity — depression, trauma, ADHD.
- Drug-specific factors — speed of onset, intensity of effect, half-life.
⚠Common mistakes— Common errors
- Equating heavy use with addiction — they are different.
- Forgetting that ICD requires symptoms over a sustained period (typically 12 months).
- Treating addiction as a moral failure rather than a recognised disorder with biological and psychological roots.
AI-generated · claude-opus-4-7 · v3-deep-psychology