Because cluster headache is short-lasting and tends to occur during th
e early morning hours, physicians rarely witness an attack. Accurate d
iagnosis is important because effective treatments are available. The
diagnosis is made from the history of temporal pattern, reddening and
tearing of the affected eye, and ipsilateral nasal congestion. An addi
tional diagnostic aid is to invite patients to demonstrate how they re
spond to attacks. The pain, one of the worst known, causes extreme res
tlessness. 50 patients showed how they walk around, sit (or kneel) and
rock, and clutch the affected side of the head. Diagnostic value apar
t, the patient will often be relieved to learn that bizarre behavioura
l responses are not a mark of insanity.