A growing number of insomnia sufferers are looking for a better night’s sleep under a weighted blanket, reports Psychology Today.

These trendy blankets are filled with pellets, balls, or chains, which give them their heft. Fans of the blankets say the pressure feels like a firm hug, giving new meaning to the word “comforter.”

The idea has intuitive appeal. It could explain why some people prefer to sleep under a heavy blanket even in warm weather. Scientific research on weighted blankets is limited, however. Here’s what is known—and what isn’t—about how well the blankets work for easing insomnia in adults.