Diazepam, 5 to 20 mg, before bedtime, was administered to six subjects in nine experiments for periods from 26 to 98 days, with reduction in night terror incidence from a mean of 1.97 (range .5 to 4.0) to .48 per night (significant at p < .05). Night terrors were reduced by an average of 80.5% (range 33% to 100%) in eight instances where frequency was reduced.
Fisher C, Kahn E, Edwards A, Davis DM. A Psychophysiological Study of Nightmares and Night TerrorsThe Suppression of Stage 4 Night Terrors With Diazepam. Arch Gen Psychiatry. 1973;28(2):252-259. doi:10.1001/archpsyc.1973.01750320082013