Just as aspirin can reduce a fever without curing the infection that causes it, psychotherapeutic medications act by controlling symptoms. Psychotherapeutic medications do not cure mental illness, but in many cases, they can help a person function despite some continuing mental pain and difficulty coping with problems. For example, drugs like chlorpromazine can turn off the “voices” heard by some people with psychosis and help them to see reality more clearly. And antidepressants can lift the dark, heavy moods of depression. The degree of response – ranging from a little relief of symptoms to complete relief – depends on a variety of factors related to the individual and the disorder being treated.

How long someone must take a psychotherapeutic medication depends on the individual and the disorder. Many depressed and anxious people may need medication for a single period – perhaps for several months – and then never need it again. People with conditions such as schizophrenia or bipolar disorder (also known as manic-depressive illness), or those whose depression or anxiety is chronic or recurrent, may have to take medication indefinitely.

Like any medication, psychotherapeutic medications do not produce the same effect in everyone. Some people may respond better to one medication than another. Some may need larger dosages than others do. Some have side effects, and others do not. Age, sex, body size, body chemistry, physical illnesses and their treatments, diet, and habits such as smoking are some of the factors that can influence a medication’s effect.