More than 20% of young adults say they use cannabis or alcohol to help them sleep. Cannabis leads by a large margin over alcohol. Researchers warn that this strategy can disrupt sleep quality. It can increase the risk of long-term sleep problems. At the same time, it increases the risk of problems with the use of addictive substances. A study from the University of Pennsylvania confirms the negative effect of cannabis on sleep in young people. For those who started using at 15 years or earlier, the risk of sleep disorders is twice as high. Long-term use causes problems falling asleep, interrupted sleep and shorter REM phases.