Marijuana may make sleep worse, especially for regular users, study finds

It's a common assumption among marijuana users: Using weed will help you fall asleep and stay asleep. Scientists, however, aren't so sure that's true.

"This is an understudied but important area, as many people are increasingly turning to cannabis products as sleep aids," said sleep specialist Wendy Troxel, a senior behavioral scientist at RAND Corporation, who was not involved in the study.

"But we really lack solid evidence demonstrating whether cannabis helps or hurts sleep," Troxel added.

Use of weed may actually harm sleep, a new study has found. The research, published Monday in a BMJ journal, revealed adults who use weed 20 or more days during the last month were 64% more likely to sleep less than six hours a night and 76% more likely to sleep longer than nine hours a night.

Optimal sleep for adults is defined by the US Centers for Disease Control and Prevention as seven to eight hours a night.