Chronic tension headache is a condition where you have a tension headache on at least 15 days every month for at least three months. The cause of chronic tension headache is often not clear. A medicine called amitriptyline may help to prevent the headaches from occurring. Chronic tension headache is a condition where you have a tension headache on at least 15 days every month for at least three months. This can be tiring and depressing. Tension headache (also called tension-type headache) is the common type of headache that most people have at some time. It's not known exactly how common chronic tension headache is, as few studies have looked at this clearly. Some studies have estimated that around 1 in 30 of all adults have chronic tension headaches - which means they have a headache on more than half of all days for three months or more. However, it is possible that a proportion of these patients actually have developed medication-overuse headaches (medication-induced headaches) as a result of their tension headaches. Therefore, it can be difficult to be certain which is their main problem. Chronic means persistent; it does not mean severe. The severity of the headaches can vary from mild to severe. Because of the persistent nature of the headaches, however, this condition is often quite disabling and distressing, and most patients take preventative medication.