Cannabis affects sleep quality, with problems worse for those who start early, scientists claim

People who had been using since their earlier teens were twice as likely to have sleeping problems

A persons lights a joint of cannabis during a meeting of members and guests of the cannabis association ACMEFUR in celebration of San Canuto's day on the Spanish Canary island of Fuerteventura on January 18, 2014. In Spain, Canute IV or Canute the Holy a (DESIREE MARTIN/AFP/Getty Images)

People who used cannabis in their early teens are twice as likely to have severe sleeping problems in later life, according to a new study.

While the results suggested that marijuana use can negatively effect sleep quality in any user, it was most frequent in people who had used the drug since they were 15-years-old or younger.

The findings are likely to be most concerning for people who use marijuana to relax or as a sleeping aid, said lead author Jilesh Chheda, research assistant of the Division of Mood and Anxiety Disorders, Department of Psychiatry, at the University of Pennsylvania.

“This latest study found that current and past marijuana users are more likely to experience sleep problems,” he said.

“The most surprising finding was that there was a strong relationship with age of first use, no matter how often people were currently using marijuana.

“People who started using early were more likely to have sleep problems as an adult,” he added.

The study involved adults aged between 20 and 59-years-old, who responded to the National Health and Nutrition Examination Survey – a series of studies designed to assess the health and nutritional status of adults and children in the US.

1,811 of those participants reported that they had used any drugs. To assess the results, scientists defined a ‘cannabis user’ as a person with any history of using the drug, and sleep-related problems were considered severe if they occurred at least 15 days per month. When a person first used the drug, and the number of times they had used it in the past month were also analysed.

The team found that marijuana users were more likely to have difficulty sleeping, maintaining sleep, experiencing non-restorative sleep, and feeling sleepy in the daytime. People who had taken the drug before they were 15 were twice as likely to suffer these complications.

The study published in the journal ‘Sleep’ and presented at SLEEP 2014, comes after Uruguay and the US states of Washington and Colorado legalised recreational marijuana use, with the first shops opening in the latter earlier this year.

“As more people have access, it will be important to understand the implications of marijuana use on public health, as its impact on sleep in the ‘real world’ is not well known,” said senior study author, Michael Grandner, PhD, instructor in Psychiatry and member of the Center for Sleep and Circadian Neurobiology.