Insomnia is a sleep trouble in which the patient has difficulties in falling or in staying asleep. There are patients who fall asleep easily, but wake up too early; others have troubles in falling asleep and a third category has troubles with both falling and staying asleep. Independent of the type of insomnia, the final result is a poor-quality sleep, responsible for depressive or irritable mood, loss in concentration, learning and memory capacities. Sleep is essential to emotional and physical health. Inadequate sleep over a period of time is increasing the risks for obesity, diabetes, heart disease and depression. People suffering of chronic insomnia show an increased predisposition for psychiatric problems. People who had sleep troubles reported impaired ability to fulfill tasks involving memory, learning, logical reasoning and mathematical operations. New studies show that insomnia might be a result of the decrease of gamma-aminobutyric acid (GABA), a neurochemical responsible for the decrease of activity in many brain areas. Lower brain GABA levels were also found in people with major depressive disorder and anxiety disorders. Hypnotics, such as benzodiazepines are acting increasing the activity of the GABA neurons. Exposure to stress is associated with a greater risk for insomnia, with individual differences. Stress activates the sympathetic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis. Increased activity of HPA axis is stimulating the secretion of corticotropin-releasing hormone, further inducing sleep disruption. Insomnia is also associated with depression and anxiety disorders, in which the HPA axis is characteristically overactive. People who show predisposition to sleep troubles have a hyperactive sympathetic nervous system, they are usually suffering from hyperarousal and they have a more intense response to stressful events. Primary sleep troubles (insomnia) has no apparent causes, is lasting more than one month, and is affecting approximately a quarter of the adult population. Secondary insomnia is associated with chronic heart and/or lung diseases, medication which interfere with onset or duration of sleep, constant change of the sleep habits, restless leg syndrome, etc. Besides lifestyle changes and cogn itive-behavioral therapy, in the treatment of insomnia are used hypnotic medicines, advised to be prescribed on short-term cures of one or two weeks. Benzodiazepines are inducing and maintaining sleep. Longer use is responsible for severe side effects--dependency and withdrawal syndrome, daytime drowsiness and dizziness, low blood pressure, memory troubles and change in the melatonin secretion during night-time period. For these reasons were created non-benzodiazepines hypnotics--zolpidem, zaleplon, which are as effective as benzodiazepines, but have fewer side effects. Nevertheless the use of these hypnotics is also restricted to 7-10 days. Zopiclone (Imovane) another short-acting non-benzodiazepine hypnotic has a different chemical structure, but a pharmacologic profile similar to that of the benzod iazepines; the treatment should be of maximum four weeks. Besides generally known concerns related to the use of hypnotics (residual sedative effects, memory impairment, rebound insomnia, abuse, dose escalation, dependency and withdrawal problems) it was signaled a risk of death associated with the use of current hypnotic medications.