The use of legal substances (such as caffeine, alcohol and tobacco) is the most common type of substance use. A person’s age, sex, cultural background and social environment can influence their substance use. People use alcohol and other drugs for a range of reasons and consumptions patterns can vary drug to drug.

Alcohol and other drugs can affect the physical, psychological, mental, social, financial and legal wellbeing of the user, their family and friends, work colleagues, and the wider community.

The use of any substance which affects the mind has the potential to cause harm, and the likelihood of harm occurring increases with greater amounts used.

People tend to choose substances that help them in some way, such as increasing pleasure, or decreasing emotional or physical pain.

The choice of substance is influenced by the particular needs the person is trying to meet. The same drug may be experienced by different people in different ways, which may impact their particular pattern of use (Australian Psychological Society).