Antidepressant medications are used to treat the persons suffering from mild to severe depression in order to relieve the symptoms, by correcting chemical imbalances of neurotransmitters in the brain.
Antidepressants can be used alone or in combination with other medications. To establish efficacy, an antidepressant must show that it can produce a therapeutic effect for the condition for which it is taken.
An antidepressant should be more efficacious than placebo to justify the risk associated with side effects. Between 30% and 50% of individuals treated with a given antidepressant do not show a response.