[Nicotine as an antidepressant and regulator of sleep in subjects with depression]

Depression is a chronic and heterogeneous disorder manifesting itself by mood and sleep irregularities which ultimately can lead to suicide. Depressed individuals have a higher tendency to smoking compared to non-depressed people, and the interruption of this dependence produces even more depression. This situation may be reverted by the administration of anti-depressives and/or the use of nicotine replacement therapies. Taking into account these observations it will be explained how nicotine possibly acts in relation to two main neurotransmitters: serotonin and dopamine; and as a neuroprotective agent under a depressive condition. The effect of nicotine as a sleep regulator in depressed subjects will also be presented. AIM. To describe and discuss the evidences showing that nicotine has anti-depressive properties.

In order of finding are presented in the following pages evidences showing that nicotine therapeutically can be used as an anti-depressive agent: general aspects of nicotine action (pharmacology, metabolism, nicotinic receptors), general features of depression, nicotine interactions in depressive disorders, and nicotine and the regulation of sleep.

Even though the basis of the relationship 'nicotine-depression' is not clear, the suggested anti-depressive role of nicotine involves a direct action over dopaminergic and serotoninergic activity or a possible indirect action as a neuroprotective agent, events which may have therapeutic effects on the quality of sleep and enhancement of depressive symptoms.