Antidepressant

Drugs useful in depression act by increasing synaptic levels of serotonin, norepinephrine, or less commonly dopamine.The term antidepressant is a misnomer for this diverse class of drugs, however, because their spectrum of action is much broader than depression.


These drugs are also effective in treating fear-based anxiety disorders such as panic disorder and generalized anxiety disorder.

In high doses, the selective serotonin uptake inhibitors are effective for obsessive-compulsive disorder.

The antidepressants are effective in the treatment of depression, but only moderately so. Many patients require sequential trials with a number of different drugs alone or in combination to achieve clinically meaningful benefit, and ~30% of patients derive no benefit at all. When pharmacologic modalities fail in depression, electroconvulsive therapy continues to be an effective treatment option.

Lithium and several anticonvulsants dampen mood swings in bipolar disorder and also treat acute manic episodes; however, residual depressive symptoms, recurrences, and significant side effects are the rule. The exact mechanism of action of lithium is not known. At therapeutic levels, lithium interacts with two important signaling pathways: (1) it blocks inositol monophosphatase, thus influencing signaling via inositol phosphates, such as IP3; and (2) it also blocks glycogen synthase kinase 3 beta (GSK3beta).