Of all the variables that factor into maintaining a state of good mental health, getting an adequate amount of restful, quality sleep each night ranks at or near the top of the list, reports the Altoona Mirror.

“Sleep is very important,” said Dr. Joseph Antonowicz, medical director of UPMC Altoona Behavioral Health Services. “We’re designed to sleep and dream.”

Particularly essential is the deeper, restorative stage of sleep that is known as rapid-eye movement (REM) sleep, in which dreaming takes place.

“If people are deprived of REM sleep, they don’t do well,” Antonowicz said. “In people with major depression, there is something known as delayed REM onset. The onset of REM is delayed, and there is less (REM) when people are depressed.