SAN FRANCISCO – Visits to the emergency department and urgent care by adolescents using marijuana in Colorado increased from 2005 to 2015, a retrospective study showed.

“Adolescents with psychiatric illness comprised a large proportion of marijuana exposures,” said lead author George Sam Wang, MD, of the University of Colorado at Denver in Aurora. “Coingestants were common and included ethanol, amphetamines, and opiates,” he said at the Pediatric Academic Societies meeting.

Dr. George Sam Wang of the University of Colorado at Denver in Aurora.

Dr. George Sam Wang

An estimated 7% of adolescents aged 12-17 years used marijuana in the past month in 2015, according to data from the National Survey on Drug Use and Health. That figure has remained fairly stable from 2004 through 2015, suggesting no effect from state legalization on national prevalence of use.

However, only eight states have legalized recreational use, and federal data may not reflect the reality within states with legalization. In Colorado, 8% of youth in that age range have used marijuana in the past month.

Dr. Wang and his colleagues therefore conducted a retrospective review of adolescent and young adult visits to the Children’s Hospital Colorado ED or any of the system’s urgent care clinics between January 2005 and December 2015. They included all individuals 13-21 years old who had a positive urine drug screen for marijuana or whose visit was coded for marijuana use (ICD-9 codes of 305.20, 969.6, or E854.1).

During those 11 years, 3,844 visits occurred, and the rate of visits related to cannabis increased from 2/1,000 emergency department/urgent care visits in 2009 to 4/1,000 in 2015. A little over half (55%) of the patients were male, and the average age was 16 years.

A nearly linear steady increase in the number of visits occurred over the study period, from 146 visits in 2005 to 639 visits in 2015. Similarly, the number of annual psychiatry evaluations increased fivefold, from 75 in 2005 to 394 in 2015. Two-thirds of the patients overall (66%) underwent a psychiatric evaluation.

The most common ICD codes reported were for unspecified cannabis use (50% of visits), unspecified episodic mood disorder (20%), and alcohol abuse (15%). Urine drug screens for alcohol were positive in 70% of the patients, while amphetamines, benzodiazepines, opiates, and cocaine were each present in 4% of the patients. Less than 1% had positive drug screens for phencyclidine, barbiturates, oxycodone, and 3,4-methylenedioxy-methamphetamine.

Close behind unspecified alcohol abuse were codes for suicidal ideation and depressive disorder, both noted in 14% of visits. Additional codes, present in 9%-12% of visits, included educational circumstance, ADHD, unspecified anxiety, unspecified asthma, and tobacco use disorder.

Just over half of all patients (53%) were discharged home. Approximately one-quarter (27%) were admitted, and 10% were transferred to another facility. Information was not provided for the remaining 10%.

“Targeted education and prevention strategies for marijuana use are necessary in the adolescent population to reduce the public health impact,” Dr. Wang said, adding that the ED should initiate behavioral health screenings and/or interventions, such as referral to treatment, with adolescents using marijuana.

Because the study was conducted at a tertiary care hospital in a state with legalized recreational marijuana, the findings are not likely generalizable, and the researchers relied only on ICD codes and drug screens without conducting full chart reviews. The data set also began 5 years after medical marijuana was legalized, precluding the ability to make in-state comparisons to when marijuana was completely illegal.

The study had no external funding. Dr. Wang disclosed he has a Colorado department of public health and environment (CDPHE) grant evaluating pharmacokinetics of cannabidiol in pediatric epilepsy patients. He also serves on a CDPHE advisory committee on health effects and impact of cannabis on public health and is a contributing author on related topics for UpToDate.