A new short-acting thieno-diazepine compound, brotizolam, has been compared to nitrazepam in a double-blind trial. Following an initial 3-day control period with no treatment, insomniac patients were allocated to 2 weeks treatment with one or the other drug according to random selection. This was then followed by a further 3-day no-drug control period. Morning and evening questionnaires were used to assess various sleep parameters and possible daytime "hang-over" effects. The patients also made actual records of the periods awake during the night (somnography). Highly significant effects were shown for both drugs in comparison to both control periods, in relation to all of the sleep parameters. However, no significant differences from either control period were demonstrated for either drug on the daytime measures, with the exception of how the patients felt at work with brotizolam and how they felt with others on nitrazepam, on both of which measures the patients felt better whilst on the drug. Comparing the figures between the initial and final no-drug control periods, did not reveal any evidence to suggest a rebound effect with either drug.