That drug appears similar to Ambien, Estorra and indiplon, but it also increases the deep slow wave of sleep.

FORBES: Sleep On Demand

Their study shows that as young people grow older they spend less of their sleeping time in slow wave or deep sleep.

BBC: Sleep linked to ageing

First the team showed that they could use the state of a region of the brain, called the medial prefronal cortex, to predict how much deep, or slow-wave, sleep a person would have.

BBC: Boosting sleep 'may slow memory rot'