[The insomnia].

Insomnia is a common pathology in the general population. It is estimated that 10 to 15 percent of the adult population has chronic insomnia and 25 to 35 percent have suffered occasional or transient insomnia due to stressful situations. The aim of this article is to provide a review of insomnia: causes, differential diagnosis, and different options of treatment. To that end we have made a search in Pubmed with the keywords "insomnia", "sleeplessness", "sleep disorders" and "pharmacological therapy". Insomnia evaluation includes a careful sleep history, personal and family history of mental and organic illness, and a registration of drug and medication intake. Authors agree that treatment should be based primarily on etiology, and secondarily on symptomatology.