OBJECTIVE: The present review addresses the relationship between sleep and depression and how serotonergic transmission is implicated in both conditions. METHOD: Literature searches were performed in the PubMed and MedLine databases up to March 2010. The terms searched were "insomnia", "depression", "sedative antidepressants" and "serotonin". In order to pinpoint the sedative antidepressants most used to treat insomnia, 34 ISI articles, mainly reviews and placebo-controlled clinical trials, were selected from 317 articles found in our primary search. RESULTS: Sleep problems may appear months before the diagnosis of clinical depression and persist after the resolution of depression. Treatment of insomnia symptoms may improve this comorbid disease. Some antidepressant drugs can also result in insomnia or daytime sleepiness. Serotonin (5-HT) demonstrates a complex pattern with respect to sleep and wakefulness that is related to the array of 5-HT receptor subtypes involved in different physiological functions. It is now believed that 5HT2 receptor stimulation is subjacent to insomnia and changes in sleep organization related to the use of some antidepressants. CONCLUSION: Some drugs commonly prescribed for the treatment of depression may worsen insomnia and impair full recovery from depression. 5-HT2 receptor antagonists are promising drugs for treatment strategies since they can improve comorbid insomnia and depression.
Neurochemistry; Antidepressive agents; Sleep; Depressive disorder; Psychopharmacology