Marijuana use could explain excessive daytime sleepiness in some teens

Last updated: 15 February 2015 at 12am PST

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Narcolepsy - extreme bouts of sleepiness that can strike at any time - affects around 1 in 2,000 people in the US. A new study raises concerns about its diagnosis in adolescents, after it identified marijuana in the urine of some teenagers who had symptoms consistent with narcolepsy.

Researchers found that more than 40% of adolescents whose urine tested positive for marijuana had symptoms consistent with narcolepsy.

The researchers, including senior author Dr. Mark L. Splaingard, director of the Sleep Disorders Center at Nationwide Children's Hospital in Columbus, OH, publish their findings in the Journal of Clinical Sleep Medicine.
Onset of narcolepsy is most likely to begin in childhood or adolescence. Excessive daytime sleepiness (EDS) is one of the most common symptoms, whereby an individual suddenly falls asleep, regardless of whether or not they have had sufficient sleep. Other symptoms may include sudden episodes of muscle weakness, called cataplexy, hallucinations and sleep paralysis.
In order to diagnose narcolepsy, a patient will typically undergo an evaluation for EDS before completing a standardized multiple sleep latency test (MSLT). This assesses how quickly the patient falls asleep in a quiet environment during the day.
MSLT also assesses patients' rapid eye movement (REM) sleep; people with narcolepsy tend to enter REM sleep within minutes of falling asleep, while those without the condition usually take around 80-100 minutes to enter REM sleep.
However, according to Dr. Splaingard and colleagues, past research in adults has indicated that if patients have used illicit drugs or a number of different medications - identified through urine samples - this could influence the results of MSLT.

Findings show urine drug screening is important prior to narcolepsy diagnosis

In this latest study, the researchers set out to determine the rate of positive urine drug screens among 383 children and adolescents who were undergoing MSLT for diagnosis of narcolepsy.
Positive urine drug screens were only identified among adolescents over the age of 13.
Of the adolescents whose urine tested positive for marijuana, 43% had MSLT results consistent with narcolepsy or abnormal REM sleep patterns. Males were most likely to have both positive drug screens and narcolepsy-consistent MSLT results.
The researchers say their findings indicate that marijuana use may be linked to EDS in some adolescents, and that urine drug screening should form a part of clinical evaluation for narcolepsy.
Dr. Splaingard adds:

"Our findings highlight and support the important step of obtaining a urine drug screen, in any patients older than 13 years of age, before accepting test findings consistent with narcolepsy, prior to physicians confirming this diagnosis.
Urine drug screening is also important in any population studies looking at the prevalence of narcolepsy in adolescents, especially with the recent trend in marijuana decriminalization and legalization."

In June 2014, Medical News Today reported on another study associating marijuana use with sleep problems. Led by researchers from the University of Pennsylvania, that study found that the earlier people start using marijuana, the more likely they are to develop sleep problems later in life.
Written by Honor Whiteman