Substance abuse is when you take drugs that are not legal. Substance abuse refers to the harmful or hazardous use of psychoactive substances, including alcohol and illicit drugs. Psychoactive substance use can lead to dependence syndrome - a cluster of behavioural, cognitive, and physiological phenomena that develop after repeated substance use and that typically include a strong desire to take the drug, difficulties in controlling its use, persisting in its use despite harmful consequences, a higher priority given to drug use than to other activities and obligations, increased tolerance, and sometimes a physical withdrawal state. Excessive use of alcohol, prescription medicine, and other legal substances too much or in the wrong way can lead to various disorders. Persons who develop a substance use problem have depression, attention deficit disorder, post-traumatic stress disorder, or another mental problem. A stressful or chaotic lifestyle and low self-esteem are also common
