Table 1 Patients likely to be referred to level 3 (adapted from [1])

Patients with:

 • refractory disabling headache of any type;

 • cluster headache and other trigeminal autonomic cephalalgias, at first presentation;

 • MOH involving drugs of dependence, where personality mitigates against successful withdrawal of medication, or where withdrawal attempts have failed;

 • high and low CSF-pressure headaches;

 • trigeminal and other cranial neuralgias or painful lesions of the cranial nerves;

 • rare primary or secondary headaches;

 • headaches with severe physical and/or psychological comorbidities.

Cases:

 • of persisting diagnostic uncertainty;

 • where risk of serious underlying disorders demands specialist investigation;

 • of other probable or certain serious secondary headache.

Patients who may participate in specific level-3 research projects (including clinical trials).