[Primary insomnia].

Primary insomnia is relatively common. According to The International Classification of Sleep Disorders, primary insomnia is a syndrome mainly composed of psychophysiological insomnia, paradoxical insomnia and idiopathic insomnia. Primary insomnia is difficulty initiating sleep (sleep onset insomnia), difficulty maintaining sleep (mid-sleep awakening, early morning awakening) or chronic non restorative sleep, which persist longer than three weeks despite having adequate opportunity for sleep and result in impaired daytime functioning. Primary insomnia is not explained by currently known psychiatric disorders, medical conditions, substance use disorders. Primary insomnia is a non-organic, unknown etiology, middle-aged female predominant sleep disturbance. Recent findings suggest the hyperarousal hypothesis of primary insomnia. In the near future, non restorative sleep might be excluded from the definition of primary insomnia.