Skip to content
Home » NPS: The Ever-Changing Challenge of “Legal Highs”

NPS: The Ever-Changing Challenge of “Legal Highs”

Novel psychoactive substances (NPS), also known as “legal highs,” refer to synthetic substances that are designed to mimic the effects of established illicit drugs like cannabis, cocaine, and MDMA. These substances have emerged as an evolving public health concern over the past two decades.

The term “novel” reflects the fact that these substances are newly created, not controlled under international drug laws, and constantly changing to evade regulation. Hundreds of NPS have flooded markets worldwide, with over 800 detected between 2009 and 2019 alone. They are inexpensive to produce and are often marketed as “legal” and “safe” alternatives to illicit drugs, making them popular among recreational drug users. However, most NPS have never been tested in humans and their effects are highly unpredictable.

NPS are synthesized in underground labs, predominately in China and India, before being sold online as “research chemicals” or in head shops as “herbal highs” or “bath salts.” This pseudo-legal sale exploits loopholes in drug laws that prohibit substances by name, not chemical structure. NPS manufacturers intentionally tweak molecular structures of banned drugs to create new, unregulated analogues faster than legislation can keep up.

Compounding risks for users is the complete lack of quality control in NPS production and distribution. Products are rarely pure, often containing mixtures of substances and adulterants. Ingredients and concentrations are unknown and vary batch to batch. Possession and sales also occur through street dealers. These unpredictable and unregulated NPS represent an alarming public health concern.

Health harms from NPS use can be severe, acute, and long-lasting. Adverse effects most commonly reported are tachycardia, agitation, anxiety, seizures, hallucinations, aggression, and psychosis. NPS have also been associated with organ damage, cascade serotonin toxicity, dependence, and death, especially among mixtures with other illicit drugs like cocaine or MDMA. Synthetic cannabinoids are linked to multiple deaths. Health risks are amplified by users being unaware of what substance(s) they are ingesting.

Prevalence of NPS use is difficult to estimate given limited detection in common drug screenings. However, studies suggest lifetime use between 0.4% and 42% among targeted young adult samples. Use is especially high among vulnerable populations like homeless youth, nightclub attendees, and men who have sex with men. The Internet has enabled global accessibility.

Several behavioral and structural factors may be driving use. Seeking legal alternatives, curiosity and experimentation, boredom, and perceptions of safety compared to illicit drugs are common motivations. The tech-savvy generation is also drawn to buying products online. Low prices point to economics being a driver. Social influences, availability, and escape from stress also play a role.

The growing NPS phenomenon requires robust, collaborative public health strategies:

Improved NPS surveillance and user monitoring are needed to track trends. Clinicians should be educated on symptoms of use.
People must be made aware of the dangers of NPS, especially youth targeted by marketing. Harm reduction education should address risks of drug combinations.
Advancements in forensic and toxicological detection will help analyze NPS contents and inform clinical care.
Legislation and law enforcement against manufacturing and distribution need to be bolstered, targeting the supply chain.
Internet sales must be disrupted. Retailers and social media platforms should face penalties for allowing sales.
Drug treatment programs should prepare for NPS-related problems, including psychosis and dependence.

NPS represent an alarming frontier of recreational drug use and a serious, evolving public health threat. Concerted efforts across sectors are needed to curb this growing, ever-changing issue and protect those most at risk.