Although many serotonin (5-hydroxytryptamine; 5-HT) receptors have been identified, our knowledge of many of the subtypes is limited. However, we do know that 5-HT1A agonists are involved in the treatment of certain anxiety disorders, that 5-HT1C and 5-HT2 receptor antagonists may be indicated for the treatment of generalized anxiety disorder, and that 5-HT1D receptor agonists are used in the treatment of migraine. Recent research has identified that various abnormalities in serotonergic function are involved in the pathogenesis of depression and anxiety, and has facilitated the development of new pharmacological agents with great therapeutic potential, for example the selective serotonin reuptake inhibitors (SSRIs). These agents appear to be effective in the treatment of many anxiety states and may have greater efficacy than other agents in the treatment of certain affective disorders. As the central serotonergic system continues to be "mapped", newer and more selective drugs are likely to be introduced, thereby possibly improving the overall successful management of depression and anxiety disorders.