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Physical dependence
Physical dependence means the body has adapted to repeated exposure to a substance. If the substance is reduced or stopped, withdrawal symptoms can occur. Dependence can develop with prescribed medicines even when they are taken exactly as directed.
Addiction
Addiction is broader. It involves a problematic pattern of use or behaviour characterised by impaired control, increasing priority and continuation despite harm.
What this page is anchored to
We summarise guidance in original plain English. Open the primary sources if you want to check the underlying recommendations.
Tolerance
Tolerance means a person may need a larger amount to achieve an effect that previously occurred at a lower amount. It can be relevant clinically, but tolerance alone does not prove addiction.
Labelling every person who develops physical dependence as “addicted” can create unnecessary stigma. Equally, a person can have a serious addictive pattern even if dramatic physical withdrawal is not present.
This page provides general educational information and does not replace assessment or advice from a healthcare professional. If you are worried about severe withdrawal, overdose, immediate danger or a mental health emergency, use our urgent help guidance.