Tension-type headache and migraine are the second and third most prevalent diseases in the world according to the Global Burden of Disease Study 2010 (only dental caries is more common). Migraine is the 7th leading specific cause of disability, responsible for almost 3% of all disability and more than half of all disability arising from neurological disorders. Migraine is the cause of an estimated 400,000 lost days from work or school every year for each million of the population in developed countries.

Some headache disorders are characterised by headache occurring on more days than not. These include medication-overuse headache, which is caused by mistreatment of headache. This together with tension-type headache may be responsible for as much disability as migraine.

The headache group in the Department of Neuroscience pursues most of its activities through the Global Campaign against Headache and in association with two organisations.

• The Norwegian National Headache Centre (NKH), which is institutionally affiliated to St Olavs Hospital, has as its main objective to collect, generate and disseminate knowledge of headache disorders. It has an extensive research activity to elucidate the causes and mechanisms of headache and conduct treatment (randomised trials) and epidemiological studies.
• Lifting The Burden (LTB), is a UK-registered charitable non-governmental organisation which leads the Global Campaign against Headache in official relations with the World Health Organization (WHO). The Campaign's main aims are to measure the burden of headache worldwide, increase awareness of it and ultimately implement measures to reduce this burden. The Department of Neuroscience conducts many activities in its role as the academic partner to Lifting The Burden and academic base of the campaign.