antidepressant

An antidepressant is a medication used to treat depressive disorders and a range of other conditions by modulating neurotransmitter activity in the brain. They are commonly prescribed for major depressive disorder, anxiety disorders, obsessive-compulsive disorder, post-traumatic stress disorder, and certain chronic pain conditions, among other indications. Treatment often follows psychotherapy or initial trials of other therapeutic approaches and may involve a combination of pharmacotherapy and psychotherapy.

The most widely used classes are selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), and atypical antidepressants. SSRIs increase the availability of serotonin in the brain and are typically preferred due to favorable side-effect profiles. SNRIs affect both serotonin and norepinephrine. TCAs influence multiple neurotransmitters but are associated with more side effects and are less commonly first-line today. MAOIs require dietary restrictions and interactions with other medicines due to the risk of hypertensive crises and serotonin syndrome. Atypical antidepressants include medications with varied mechanisms, such as bupropion and mirtazapine, used in specific clinical scenarios.

Onset of benefit generally takes several weeks, and full therapeutic effects may take one to two months. Side effects vary by drug class and individual but can include nausea, sleep disturbances, sexual dysfunction, weight changes, and, rarely, increased suicidal thoughts in young people when starting treatment. Discontinuation or withdrawal symptoms may occur if a drug is stopped abruptly. Pharmacologic choices are individualized based on history, comorbid conditions, patient preference, and potential drug interactions.