The Oregon Health & Science University recently posted an on-line report (Drug Class Review on Newer Sedative Hypnotics, December 2005) that offers an answer to this question. The authors conclude that most comparisons found the newer sedative hypnotics no better than older benzodiazepine hypnotics in terms of efficacy and short-term adverse events.
The comprehensive review of clinical trials investigating the efficacy and safety of hypnotic agents covered both the older benzodiazepine sleep aids and the newer sleep aids introduced since 1992. It included 141 trials with both direct head-to-head and indirect comparisons of the newer sleep aids. The researchers found some differences among the newer sleep aids on some outcome measures, but no one drug appeared to be consistently better.