New psychoactive substances (NPS) have been a growing concern for public health and safety in recent years. Often referred to as "designer drugs" or "bath salts," these substances are chemically engineered to mimic the effects of regulated drugs like cocaine, MDMA, or LSD while evading existing legal definitions.

Manufacturers of these drugs constantly develop new chemicals to replace those that are banned, leading to a perpetual evolution in the drugs' chemical structures. This dynamic nature of NPS underscores the need for continuous vigilance and adaptation in law enforcement and regulatory measures.
These drugs also carry the unfortunate nickname of "legal highs," suggesting to some individuals that NPS fall into a legal "gray area."
Contrary to the misconception that NPS fall into a legal gray area, federal law actually regulates and prohibits most of these substances. The enforcement system is structured for agility, enabling authorities to quickly define and categorize new substances as they appear on the market. This proactive approach is designed to reassure the public about the control measures in place.
It's crucial to understand that if you're accused of possessing or trafficking NPS, you could be convicted under federal drug laws. Even if you claim uncertainty around whether the NPS meets the criteria of a controlled substance, the legal consequences can be severe. This awareness is vital in making informed decisions about NPS involvement.
Health and Social Harms
New psychoactive substances (NPS) are a diverse group of substances associated with a number of health and social harms on a person and societal level.

NPS toxicity and dependence syndromes are recognized in primary care, emergency departments, psychiatric inpatient settings, and community care settings, underscoring the need for caution.
One realistic classification system is to divide NPS into groups, such as synthetic stimulants, synthetic cannabinoids, synthetic hallucinogens, synthetic depressants, synthetic opioids, and benzodiazepines.
As noted above, new psychoactive substances (NPS) are a complex and diverse group of substances.
NPS tend to be either analogues of existing controlled drugs and pharmaceutical products or newly synthesized chemicals, created to mimic the actions and psychoactive effects of licensed medicines and other controlled substances. Because of their number, nature, and composition, NPS pose significant challenges and have been described as a growing worldwide epidemic.
What Are New Psychoactive Substances?
A New Psychoactive Substance (NPS) is a substance of abuse, either in a pure form or a preparation, not controlled by the 1961 Single Convention on Narcotic Drugs or the 1971 Convention on Psychotropic Substances, but might pose a public health threat.

NPS that have been placed under international control since 2015 continue to be included under the term NPS to enable time series analysis. For instance, substances like mephedrone and methylenedioxypyrovalerone (MDPV) have been placed under international control.
As noted above, new psychoactive substances (NPS) are substances designed to mimic the effects of controlled drugs while attempting to avoid classification under existing drug schedules.
The term "new" here does not necessarily refer to newly invented substances (since many NPS have existed for some time) but rather their recent introduction for consumption as recreational drugs.
Unlike traditional drugs, NPS often have slightly modified chemical structures, making them appear distinct from substances explicitly listed as illegal in federal statutes. These drugs are usually synthesized in underground labs and marketed with misleading labels like "not for human consumption" to create an illusion of legality.
Examples and Drug Names
- Synthetic cannabinoids: Marketed under names like K2 or Spice, these substances are intended to replicate the effects of THC, the active ingredient in marijuana. However, they are far more potent and unpredictable, leading to severe health risks, including psychoses, seizures, and even death.
- Synthetic cathinones: Known as "bath salts," these stimulants are designed to mimic drugs like MDMA or methamphetamine. They are associated with dangerous side effects, such as agitation, hallucinations, and violent behavior.
Other names include Synthetic drugs, legal highs, herbal highs, party pills, synthetic cocaine, synthetic cannabis, herbal ecstasy, NBOMes, bath salts, plant fertiliser, herbal incense, room deodorisers, aphrodisiac tea, social tonics, new and emerging drugs (NEDs), drug analogues and research chemicals.
What are the Risks of NPS?
The use of NPS is frequently linked to health problems. Typically, the side effects of NPS include the following:
- Seizures,
- Agitation,
- Aggression,
- Acute psychosis,
- Potential dependence.
NPS users have often been hospitalized with severe intoxications. Safety data on the toxicity and carcinogenic potential of many NPS are limited, and information on long-term adverse effects or risks is still mostly unknown.
Purity and composition of products containing NPS are often not known, which places users at high risk, as evidenced by hospital emergency admissions and deaths associated with NPS, often including cases of poly-substance use.
NPS Regulated Under Federal Law
Federal authorities have adapted existing drug laws to address the challenges posed by NPS. Several statutes and provisions within U.S. law address their manufacture, distribution, and use. These laws are designed to provide robust enforcement powers while closing loopholes that NPS creators try to exploit. Let's review them below.
The Controlled Substances Act (CSA)
The CSA categorizes drugs into five drug schedules based on their potential for abuse, accepted medical use, and safety profile.
Substances listed in Schedule I are considered illegal for all purposes except limited research. Many NPS are listed under Schedule I, effectively banning their manufacture, sale, possession, and use. For instance, certain synthetic cannabinoids and cathinones are specifically named in Schedule I, making them explicitly illegal.
The Federal Analogue Act (21 U.S.C. § 813)
The Federal Analogue Act addresses substances that are not specifically listed in the CSA. Under this law, a substance can still be treated as a Schedule I or II drug if it:
- Has a chemical structure substantially similar to that of a scheduled substance,
- Is intended for human consumption, and
- Has a similar or greater effect on the central nervous system as a scheduled drug.
This provision enables federal prosecutors to target unscheduled NPS by demonstrating their chemical similarity to controlled substances.
21 U.S. Code 813 - Treatment of controlled substance analogues says, "(a) A controlled substance analogue shall, to the extent intended for human consumption, be treated, for any Federal law, as a controlled substance in schedule I."
DEA Emergency Scheduling Authority (21 U.S.C. § 811(h))
To address emerging threats quickly, the Drug Enforcement Administration (DEA) has the authority to temporarily classify a substance as Schedule I for up to two years (with a possible one-year extension) if it poses "an imminent hazard to public safety."

This tool has been used frequently in recent years to ban substances like synthetic cannabinoids ("Spice," "K2") and synthetic cathinones ("bath salts") while Congress considers permanent scheduling.
21 U.S.C. 811(h)(1) says, "Temporary scheduling to avoid imminent hazards to public safety. If the Attorney General finds that the scheduling of a substance in schedule I on a temporary basis is necessary to avoid an imminent hazard to the public safety, he may, by order and without regard to the requirements of subsection (b) relating to the Secretary of Health and Human Services, schedule such substance in schedule I if the substance is not listed in any other schedule in section 812 of this title or if no exemption or approval is in effect for the substance under section 505 of the Federal Food, Drug, and Cosmetic Act [21 U.S.C. 355]."
Are Any NPS Legal?
Technically, some NPS are not yet scheduled and may not meet the chemical similarity requirement under the Analogue Act. However, marketing or selling such substances for human consumption can still be risky.

Prosecutors may use other laws, such as FDA misbranding statutes (21 U.S.C. 331), to bring charges for selling unapproved drugs or unsafe products.
Put simply, even if a substance isn't specifically listed or covered by the Analogue Act, you can still be prosecuted under existing federal drug laws if you're caught distributing or using it in a way that implies it's for human use.
Bear in mind that federal penalties for possessing or distributing NPS can be just as severe as those for traditional drugs, amounting to stiff fines and many years in prison.
Several countries and territories where a large number of different NPS have rapidly emerged have adopted controls on entire substance groups of NPS using a generic approach, or have introduced analogous legislation that invokes the principle of "chemical similarity" to an already controlled substance to control substances not explicitly mentioned in the legislation.
Defense Strategies
If you've been charged with an offense involving an NPS, a federal criminal defense attorney may challenge:
- Whether the substance meets the chemical similarity requirements under the Analogue Act.
- Whether there was sufficient evidence of intent for human consumption.
- Whether the DEA properly followed procedures under emergency scheduling rules.
- Or whether your Fourth Amendment rights were violated during a search or seizure.
Because these are complex and highly technical cases involving expert testimony and forensic chemistry, it's critical to consult with a federal criminal defense attorney who understands both the science and the law behind NPS prosecutions.
For additional information, contact Eisner Gorin LLP, a federal criminal defense law firm located in Los Angeles, California.
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