Antidepressants are a class of medications used to treat major depressive disorder, anxiety disorders, chronic pain, and addiction. Common side effects of antidepressants include dry mouth, weight gain, dizziness, headaches, sexual dysfunction, and emotional blunting. There is an increased risk of suicidal thinking and behavior when taken by children, adolescents, and young adults. Discontinuation syndrome, which resembles recurrent depression, may occur after stopping any antidepressant. Research regarding the effectiveness of antidepressants for depression in adults has found both benefits and drawbacks. Evidence of benefit in children and adolescents is unclear. A 2018 study found that the 21 most commonly prescribed antidepressant medications were more effective than placebo for the short-term (acute) treatments of adults with major depressive disorder. However, other research has found that the placebo effect may account for most or all of the drugs' observed efficacy. Research on the effectiveness of antidepressants is generally done on people who have severe symptoms, a population that exhibits much weaker placebo responses, meaning that the results cannot be extrapolated to the general population. Non-pharmaceutical treatments for depression can also be effective instead of, or in conjunction with, medications. Medical uses Antidepressants are prescribed to treat major depressive disorder (MDD), anxiety disorders, chronic pain, and some addictions. Antidepressants are often used in combination with one another. Proponents of the monoamine hypothesis of depression recommend choosing an antidepressant with the mechanism of action impacting the most prominent symptoms. Under this practice, for example, a person with MDD who is also anxious or irritable would be treated with selective serotonin reuptake inhibitors (SSRIs) or norepinephrine reuptake inhibitors, while a person suffering from loss of energy and enjoyment of life would take a norepinephrine–dopamine reuptake inhibitor. Major depressive disorder The UK National Institute for Health and Care Excellence (NICE)'s 2022 guidelines indicate that antidepressants should not be routinely used for the initial treatment of mild depression, "unless that is the person's preference". The guidelines recommended that antidepressant treatment be considered: For people with a history of moderate or severe depression For people with mild depression that has been present for an extended period As a first-line treatment for moderate to severe depression As a second-line treatment for mild depression that persists after other interventions The guidelines further note that in most cases, antidepressants should be used in combination with psychosocial interventions and should be continued for at least six months to reduce the risk of