Safer Tripping: Serotonergic Psychedelics and Drug Checking. Submission and Detection Rates, Potential Harms, and Challenges for Drug Analysis

Hirschfeld and colleagues situate this review within the expanding role of drug checking (DC) as both a harm-reduction intervention and a market-monitoring tool. DC services allow people to anonymously submit samples for chemical analysis and typically pair results with brief counselling; they have historically focused on stimulants such as MDMA, amphetamine and cocaine but face a more complex illicit market with a rising diversity of substances. The authors note renewed scientific and public interest in serotonergic psychedelics (SPs) — including classic compounds such as LSD, psilocybin, DMT and mescaline — alongside the emergence of many novel synthetic SPs (novel psychoactive substances, NPS) whose pharmacology and toxicity are often poorly characterised. The review sets out to determine the relevance of SPs in current DC practice by examining peer-reviewed reports that provide original data on submission or detection of SPs to DC services. Specifically, the investigators sought to quantify the presence and proportion of SPs among submitted samples, to describe adulterations and analogues detected, and to discuss the physical and psychological harms associated with SPs as well as analytical challenges for DC services. The emphasis is on how DC can contribute to reducing SP-related harms given the limitations of many existing on-site analytical methods.

The study is a literature review based on a focused search strategy. The researchers searched PubMed (MEDLINE) using the terms "drug checking" OR "pill testing" OR "drug safety testing", and supplemented this with hand-searching of references and screening Google Scholar. Inclusion criteria were peer-reviewed articles published between January 1980 and March 2021 in English, Dutch, or German that provided original information on submission or detection of SPs by international DC services. The search returned 184 records from PubMed, of which 14 contained original DC data on SPs; one further report was identified by manual search, yielding 15 reports in total. All included reports were published from 2005 onward and provided data from DC services in several countries (Netherlands, Spain, UK, Italy, Portugal, Belgium, Canada and Australia). The extracted text does not describe a formal risk-of-bias assessment or meta-analytic pooling methods, nor does it specify additional screening or data-extraction procedures beyond the database and manual searches.

The review identified 15 peer-reviewed reports describing SPs in samples submitted to DC services across multiple countries. Overall, SPs comprised a relatively low but apparently increasing share of submissions, with notable variation between services, event types (stationary versus on-site festival testing) and jurisdictions. Key findings by jurisdiction included: the Dutch DIMS service detected many SP types — 11 different tryptamines and 19 psychedelic phenethylamines between 2013 and 2017 — and earlier data (1999–2010) showed LSD and 2C-B as the most prevalent SPs submitted; the number of LSD submissions rose from 6 in 1999 to 66 in the first half of 2010, and about 80% of samples submitted as LSD contained LSD overall, though annual figures varied widely (e.g. 26% in 2002, >95% in 2007). In Spain, Energy Control reported that tryptamines represented 1.7% of 25,296 submitted samples over 2006–2015, with roughly half of tryptamine submissions being regulated substances; 4-AcO-DMT, AMT and 5-MeO-DMT were among the most frequently detected tryptamines, and 2C-B was a common NPS adulterant in MDMA tablets. From the UK, a stationary service reported that 12.2% of 171 samples were submitted as SPs and that SPs were detected in 14.6% of samples; on-site festival testing by The Loop found LSD in 0.9% and NPS in 1.3% of 247 samples, with 19.5% of all samples mis‑sold and higher adulteration rates for onsite purchases (27%) than offsite (12%). Canadian on-site DC at festivals found 4.2% of 336 samples expected to be SPs and detected multiple NPS including 2C-x (n = 7) and many unknown substances. At Portugal’s Boom festival, 29.7% of 753 samples were expected to be SPs; LSD was the second-most tested substance and while 2C-B samples were unadulterated, 11.6% of expected LSD samples contained NBOMe or DOx instead. In a separate Boom dataset (2014), of 245 LSD submissions 67.3% contained LSD only, 0.8% had adulterations, 7.8% contained no psychoactive substance and 24.1% contained another psychoactive instead (DOx 11.4%, NBOMes 9.8%). Italian festival testing (27 events) identified 18 SPs among 472 submissions (3.8%), 13 of which were NPS (2.8%) including NBOMes and 2C-x; mis‑sold SPs comprised 2.1%. Australian and Belgian reports noted isolated findings: an Australian 2005 festival study alleged SP adulteration of ecstasy pills but lacked analytic resolution, while Belgium’s Modus Vivendi detected 5-MeO‑MiPT and N‑Et‑2,3‑MDPEA among two of 287 samples sold as amphetamine, cocaine or ketamine (2018–2019). Across reports, a substantial proportion of adulterations and mis‑sold samples contained novel SPs — notably phenethylamine derivatives such as 2C‑x, DOx and NBOMes — which often have unknown toxicological profiles. Several studies highlighted that detection of these novel SPs frequently requires high-sensitivity analytical techniques not available at many on-site DC services. The extracted text does not provide pooled quantitative estimates of prevalence across studies beyond the individual report figures.

Hirschfeld and colleagues interpret the collected evidence as indicating that SPs currently represent a minority but growing fraction of samples submitted to DC services, with considerable heterogeneity across countries and between stationary and on-site testing. The review emphasises three main points: SPs are present at low but rising rates in DC submissions; unexpected SPs are commonly detected in samples originally sold as non-psychedelic drugs; and adulterations or analogues consisting of novel SPs are relatively frequent across services. The authors align these findings with broader monitoring data from the EMCDDA and UNODC, which also report an increasing share of SP-class NPS among newly recorded substances. They argue that the unpredictability and often unknown toxicology of novel SPs — especially NBOMes and other phenethylamine derivatives that can be highly potent full 5‑HT2a agonists — pose specific public-health risks. The discussion summarises reported harms associated with novel SPs, ranging from severe sympathomimetic and serotonergic toxicity to fatalities, and notes subacute and persistent psychological effects such as psychosis, HPPD and depersonalisation syndromes. The authors highlight particular hazards of NBOMes: sub‑milligramme active doses, variable distribution on blotter papers, and a documented series of intoxications and deaths. Turning to implications for DC, the investigators stress that effective harm reduction depends on analytical accuracy. High-sensitivity "hyphenated" methods (liquid or gas chromatography coupled with mass spectrometry) and reference standards are required for reliable detection and quantification, but such techniques are costly and often confined to laboratory settings. Portable or qualitative methods (FTIR, Raman, TLC, reagent tests) can detect abundant constituents on-site but have limited sensitivity for adulterants and newly emerged compounds and may lack reference spectra for novel NPS. Legal and practical constraints may further limit some services; for example, non‑contact methods like Raman can reduce juridical risk in jurisdictions where possession by staff is problematic. Given these constraints, the authors recommend that DC services without advanced on-site capabilities collaborate with analytical laboratories, provide clear communication about analytical limitations to service users, and integrate DC into a broader, evidence-informed public‑health strategy. They acknowledge that their review is limited to peer‑reviewed reports from different years and is therefore not a comprehensive global census of SP submissions.

The authors conclude that the rising interest in SPs and the risks posed by novel synthetic psychedelics justify investment in advanced analytical techniques for DC services or, alternatively, formal collaboration with laboratories able to provide sensitive detection and quantification. Although submissions of SPs to DC services remain comparatively low and analyses are costly, DC is valuable for raising awareness about SP adulteration in non‑psychedelic samples, for informing harm‑minimisation strategies among hard‑to‑reach user groups, and for market monitoring. They highlight the particular utility of DC for identifying hazardous novel phenethylamine psychedelics such as NBOMes, which have been found in samples sold as LSD or MDMA and can have higher toxicity and unpredictable duration. Finally, the authors recommend that DC be embedded within a comprehensive, well‑informed drug‑policy and public‑health approach to address SP‑related harms.