Brain serotonin and the mechanism of action of selective serotonin re-uptake inhibitors (SSRI)

Summary le of serotonin (5-HT) in the human central nervous system and its involvement in a variety of physiological and behavioral functions are summarized. The main items of the 5-HT hypothesis of depression, and the role of 5-HT in the pathophysiology and treatment of this mood disorder are considered. The main pathogenetic hypotheses and drug treatment of depression are also briefly reviewed. New data on the administration of selective 5-HT re-uptake inhibitors (SSRI) and their mechanisms of action are discussed. Their relative safety, and the lack of cognitive impairments associated with their use are in favor of their utilization in the treatment of older patients. However, it is emphasized that evidence-based treatment strategies of depression in the elderly patients have not yet been identified and this lack of scientific evidence might be associated with the problem of under-diagnosis and under-treatment in the daily medical practice. Finally, the recent guidelines of pharmacological treatment strategies of depression in the elderly people are reported, emphasizing the specific issues in treating older patients, such as the bio-availability, the pharmacokinetic changes, the excretion rates of medicines, etc., which all need to be conisdered when planning treatment of depression.