A series of 19 patients with what originally had been diagnosed as a first division (V1) trigeminal neuralgia was collected. The inclusion criteria were severe, rather short-lasting pain attacks within the V1 area, combined with trigger mechanisms. There were 10 women and 9 men, and the mean age of onset was 57.8 years. Fifteen of 16 with adequate information on attack duration had paroxysms of a "few seconds" duration or less, whereas 10 patients had paroxysms lasting < or = 2 seconds. In an exceptional case, only "more long-lasting" attacks (greater than 30 seconds' duration) were experienced. In regard to autonomic phenomena, lacrimation was most frequently present (in a total of 8 patients; 3 rather regularly, 5 more irregularly). The combination of lacrimation, conjunctival injection, and rhinorrhea was present in only 2 (of 19), and in neither of them in a major way. Typically, autonomic phenomena occurred during the later stages of disease and during particularly severe and long-lasting attacks. Seven of 14 with adequate information also had nocturnal attacks. Initially, a more or less complete carbamazepine effect was reported by 10 of 13 patients. Precipitation mechanisms were the same as with second and third division tic, but were mainly located within the V1 area, particularly initially. A comparison with SUNCT syndrome has been made. SUNCT is a predominantly male disorder, with only exceptional attacks of < or = 10 seconds' duration, and generally with attacks of 15 seconds or longer. Autonomic symptoms and signs are more pronounced than in V1 tic. Carbamazepine generally provides minor, if any, benefit in SUNCT. The present work strongly indicates that the two disorders are essentially different.