Research on nonbenzodiazepines is new and conflicting. A review by a team of researchers suggests the use of these drugs for people that have trouble falling asleep but not staying asleep, as next-day impairments were minimal. The team noted that the safety of these drugs had been established, but called for more research into their long-term effectiveness in treating insomnia. Other evidence suggests that tolerance to nonbenzodiazepines may be slower to develop than with benzodiazepines. A different team was more skeptical, finding little benefit over benzodiazepines.