Substance abuse refers to the harmful consumption of any mind-altering substances such as alcohol and illicit drugs. Substance abuse has a host of negative effects on health. Every year, alcohol abuse kills over 3.3 million people annually and each year, over 31 million people suffer from drug-related disorders globally.

Substance abuse leads to mental and behavioral problems, despite temporary feelings of wellbeing and control. Most mind-altering substances have addictive properties which makes it very difficult for individuals to control the amount they ingest. Substance abuse has strong mental effects whereby a higher priority is given to drug use than to other activities and obligations to work, family, and communities.

Abuse of alcohol and drugs also has effects on physical health. Prolonged alcohol abuse can lead to conditions such as liver cirrhosis and alcohol consumption can lead to increased risks from road traffic injuries and death. Drug overdoses can lead to death and are becoming a leading cause of death for young people.

Some efforts such as providing warning labels on legal substances such as alcohol, and legal drugs can help reduce the prevalence of abuse. Individual-level interventions such as counselling or support groups are also necessary so that people are able to fight their own addictions and the associated mental health effects.