<qa>  What is the main problem for patients with PTSD?Within the normal population 4-8 of the people suffer regularly from nightmares. Clinical observations show that nightmares are a common problem for patients who suffer from all kinds of psychiatric disorders, and not just for the patients diagnosed with PTSD. Often nightmares can lead to sleep disorders, which have a negative impact on emotional well-being and cognitive functioning during the day. As well as this a strong relationship between severity of nightmares and severity of psychopathology has been found. This gives a strong argument for treatment of nightmares as a symptom, separate from the psychiatric disorder. 