Drug and substance misuse is the use of illegal drugs, or over-the-counter or prescription medications in a way that they are not meant to be used. Over time, substance misuse can become an unhealthy way to respond to stress and anxiety.
Substance use disorder occurs when the use of drugs impairs your health or how you function in your daily life. Examples of this kind of impairment include problems with physical or emotional health, disability, and failure to meet major responsibilities. Substance use disorders can be mild, moderate, or severe.