Positions on the benefits of melatonin for insomnia are mixed. A review by the Agency for Healthcare Research and Quality (AHRQ) from 2015 stated that evidence of benefit in the general population was unclear. A review from 2017, found a modest effect on time until onset of sleep. Another review from 2017 put this decrease at six minutes to sleep onset but found no difference in total sleep time. Melatonin may also be useful in delayed sleep phase syndrome. Melatonin appears to work as well as ramelteon but costs less.