Self-reported use of novel psychoactive substances in a US nationally representative survey: Prevalence, correlates, and a call for new survey methods to prevent underreporting

Highlights

• 1.2% of individuals in the US, age 13–34, reported use of a novel psychoactive substance.

• Use of tryptamines was most common, followed by psychedelic phenethylamines.

• Use increased from 2009 through 2013 and use of other illicit drugs was common.

• Males, whites and older or unmarried subjects were more likely to report use.

• An adaptable survey tool would improve reporting as new drugs continue to emerge.

Abstract

Background

In recent years, there has been an increase in emergence and use of novel psychoactive substances (NPS) in the US and worldwide. However, there is little published epidemiological survey data estimating the prevalence of use in the US.

Method

Data on self-reported NPS use came from the National Survey of Drug Use and Health (2009–2013), a national representative sample of non-institutionalized individuals in the US. Subjects were asked to provide names of (non-traditional) drugs they used that they were not specifically asked about. We examined lifetime prevalence and sociodemographic correlates of self-reported use of new and uncommon synthetic drugs (NPS) among subjects ages 12–34-years-old.

Results

1.2% of subjects self-reported any use of the 57 NPS we examined. Use of psychedelic tryptamines (primarily DMT) was most common, followed by psychedelic phenethylamines (e.g., 2C series) and synthetic cannabinoids. Prevalence of self-reported use of NPS increased from 2009 to 2013 and use was most common among males, whites, older subjects, those of lower income, and among those residing in cities. Lifetime use of various other illicit drugs (e.g., LSD, cocaine, ecstasy/MDMA) was highly prevalent among NPS users.

Conclusion

This the first study reporting on use of a variety of NPS in a nationally representative US sample; however, use appears to be underreported as other national data suggest higher rates of NPS (e.g., synthetic cannabinoid) use. Developing more adaptable survey tools and systematically assessing NPS use would allow researchers to ask about hundreds of NPS and improve reporting as new drugs continue to rapidly emerge.

Introduction

Novel psychoactive substances (NPS) have been emerging in the US and worldwide at an unprecedented rate. In 2009, the US National Forensic Laboratory Information System (NFLIS) received drug identification reports of two synthetic cannabinoids and four synthetic cathinones (Senate Caucus on International Narcotics Control, 2013). By 2012, NFLIS received reports on 57 different synthetic cannabinoids and 31 synthetic cathinones. In Europe, 101 NPS were discovered in 2014, up from 73 in 2012, 49 in 2011 and 41 in 2010 (EMCDDA, 2012, EMCDDA, 2015). Globally, 348 NPS were reported by December 2013 to the United Nations Office on Drugs and Crime (UNODC), up from 166 in 2009 (UNODC, 2014).

NPS are often sold as “research chemicals,” “plant food” or “bath salts,” labeled “not for human consumption,” and are sold over the Internet, in head shops, or by street dealers. These (often “legal”) drugs tend to be synthetic derivatives or analogs of older, more traditional drugs such as cannabis (marijuana), ecstasy (3,4-methylenedioxymethamphetamine [MDMA]), amphetamine, and lysergic acid diethylamide (LSD). Such drugs usually become controlled, but replacement drugs with similar chemical structures are often created to continue to evade law enforcement (Cohen, 2014, Khazan, 2013).

There are hundreds of NPS and many can be classified into somewhat distinct categories. One of the largest stimulant classes that contain many NPS is the phenethylamine class, which includes synthetic cathinones (commonly referred to as “bath salts”), empathogenic stimulants (e.g., N-methyl-1,3-benzodioxolylbutanamine; MBDB), and new psychedelics (e.g., 2C or NBOMe series drugs; Hill and Thomas, 2011). There are also many other stimulant NPS (e.g., piperazines), new synthetic dissociative drugs (e.g., methoxetamine [MXE], which mimics ketamine), and other psychedelics similar to LSD. Synthetic cannabinoids, which mimic Δ-9-tetrahydrocannabinol (THC), the main psychoactive component in cannabis, have gained prevalence at a fast pace since 2008 (EMCDDA, 2015).

In recent years, numerous case reports and systematic reports from poison centers and forensic laboratories have been published to alert the medical community about rates of reported poisonings and associated adverse outcomes associated with NPS use (Dart et al., 2015, Elliott and Evans, 2014, Forrester, 2013, Forrester, 2014, Hill et al., 2014, Murphy et al., 2013, Vazirian et al., 2015). However, epidemiologic survey data is sorely needed from representative samples to estimate prevalence of NPS use generally, as well as use of specific NPS or classes of NPS.

While population surveys tend to assess self-reported use of various “traditional” psychoactive drugs (e.g., cocaine), very few national surveys ask about use of newer, less traditional drugs. Some European surveys such as the Crime Survey for England and Wales started asking about mephedrone and benzylpiperazine (BZP) in 2010 (United Kingdom Focal Point on Drugs, 2014) and the Monitoring the Future (MTF) study, a US national representative sample of adolescents in high schools, started asking students about synthetic cannabinoids in 2011 and “bath salts” in 2012 (Miech et al., 2015). However, there are now hundreds of new (or uncommon) psychoactive drugs that are not systematically assessed in these surveys.

According to NFLIS data on NPS cases analyzed by federal, state, and local forensic laboratories, there were 469 reports of synthetic cannabinoids in the first half of 2010, 23,123 reports in the first half of 2012, and 19,838 in the first half of 2014 (US Drug Enforcement Administration [DEA], 2014). Reported poisonings involving synthetic cannabinoids have skyrocketed in the US with poisonings increasing 330% in the first quarter of 2015 (Law et al., 2015). With respect to synthetic cathinones (a.k.a.: “bath salts”), reports to NFLIS increased from 142 in the first half of 2010 to 7997 in the first half of 2013 (US DEA, 2014). National and state-specific (e.g., Texas, North Carolina) Poison Control Center data also suggest that use of NPS is on the rise (Dart et al., 2015, Forrester, 2013, Forrester, 2014, Murphy et al., 2013).

MTF national survey data suggest that about 10% of high school seniors in the US (modal age: 18) have used synthetic cannabinoids and 1% have used “bath salts” in the last 12 months (Miech et al., 2015, Palamar and Acosta, 2015). Indicator data presented by the Community Epidemiology Work Group (CEWG) in the US suggests that synthetic cannabinoids and cathinones appear to be the most prevalent NPS in the US; but there are mixed patterns throughout US cities (CEWG, 2014). Rates of use of psychedelic phenethylamines (e.g., 2C-I) have begun to increase in some US cities as well. However, such indicator data tends to rely on reported poisonings, arrests, seizures, and treatment admissions. Few surveys or assessments ask about use of specific new drugs, so indicator data does not always detect increasing rates of use. Some Internet surveys have focused on users of specific NPS (Carhart-Harris et al., 2011, Johnson and Johnson, 2014), other surveys have focused on individuals at high risk for use (e.g., nightclub attendees; Kelly et al., 2013), and every year the Global Drug Survey (this year taken by users in over 50 countries) asks thousands of club-goers about use of dozens of NPS (Barratt et al., 2014, Morley et al., 2015, Uosukainen et al., 2015, Winstock et al., 2014, Winstock et al., 2015, Winstock and Barratt, 2013).

While studies of targeted samples have begun to provide rates of use of NPS in high-risk populations (e.g., club-goers), there are little to no data on these drugs from general US population samples. We utilized data from the National Survey on Drug Use and Health (NSDUH), which does not ask specifically about NPS, but allows subjects to enter names of NPS. While this method is limited, this feature helps provide much needed data as national surveys are currently lacking standard questions about NPS. We also delineated sociodemographic and other drug use correlates of use of NPS to inform prevention among subgroups found to be at risk, and provide recommendations for future surveys that assess NPS use.