Problems relating to alcohol or drugs occur across a spectrum of levels of consumption and may be physical, psychological or social in nature. At one extreme, there is a small but significant proportion of people who develop dependence and may require both intensive and extensive support. However, on a population level, huge reductions in the harm caused by psychoactive substances could be made if everyone was encouraged to use a bit less. All health and social care professionals should be able to screen for potential alcohol use disorders, deliver brief advice and refer on to specialist services where appropriate. They should also have an awareness of the common illicit drugs and the potential problems these drugs are associated with. The evidence base for treatment of substance use disorders has developed over the past 30 years, and clinicians should be positive and optimistic that meaningful change in behaviour can be achieved. Prompt referral to the right level of support and treatment may prevent future problems. Recovery support services play a crucial part in sustaining any gains made in treatment, and many people recover without using professionally directed treatment at all. It is estimated that approximately 10 per cent of the population of the USA is in remission from a substance use disorder of any severity.