The term "drug" typically refers to any substance that can alter an individual's thoughts, feelings, or behaviors. This can include both legal and illegal substances, such as prescription medications, over-the-counter drugs, and illicit drugs.

Psychologists and other mental health professionals may use drugs as a part of the treatment process for certain psychological disorders, such as depression, anxiety, and schizophrenia. These medications can help to alleviate symptoms and improve an individual's functioning and well-being. However, they can also have potential side effects and may not be appropriate for everyone, so they are typically used in conjunction with other treatment approaches, such as therapy.

Psychologists may also work with individuals who have substance use disorders, which are conditions characterized by the use of drugs in a way that causes significant impairment or distress. Substance use disorders can be caused by a variety of factors, including genetics, environmental influences, and personal history, and they can have serious negative consequences for an individual's physical and mental health. Psychologists and other mental health professionals can help individuals with substance use disorders address their substance use and related issues as part of the treatment process.