As a plant, cannabis is valued for its euphorigenic and medicinal properties, as well as its industrial importance. In nature, it is found in various habitats at almost all elevations up to the foothills of the Himalayan mountains. The history of the cannabis plant goes back to over 10,000 years. It is one of the oldest sources of food and textile fiber. Hemp grown for fiber was introduced in Western Asia and Egypt and subsequently to Europe between 1000 and 2000 BCE. Over the last few years growing of cannabis (hemp) has become a major agricultural industry in numerous countries.

Cannabis has a long history of being used as a crude drug to treat epilepsy, tetanus, rheumatism, migraine, asthma, trigeminal neuralgia, fatigue, insomnia and many other ailments in the Middle East and Asia, with references as far back as the 6th century BCE. It was introduced in Western Europe as a medicine in the early 19th century. More recently its derivatives are being used in HIV/AIDS and multiple sclerosis. The plant contains a complex mixture of compounds. It produces a unique class of terpenophenolic compounds called cannabinoids. More than 550 constituents have been isolated from Cannabis so far, out of which 129 compounds are phytocannabinoids (1, 2). The concentration of cannabinoids in the dried inflorescence (leaves and buds) is considered to be the most objective measure to classify the plant according to the degree of psychoactivity since THC and other cannabinoids are produced in the glandular trichomes predominantly found in the buds and leaves of the plant. Based on the presence of the most abundant cannabinoids, THC and CBD, in its leaves and buds, C. sativa was divided into three distinct chemotypes namely, drug type (high THC chemotype), fiber type/hemp (high CBD chemotype), and intermediate chemotype (with balanced THC and CBD levels).

Although cannabis preparations have been used over millennia for their psychoactivity, as well as for their therapeutic properties, their chemistry and biology were not well known until the last few decades. Indeed, the major psychoactive cannabis constituent, Δ⁹-tetrahydrocannabinol (THC), was isolated in a pure form, and its structure was elucidated, only in the early 1960’s (3). This is in sharp contrast with the thorough knowledge for morphine and cocaine, which were isolated during the nineteenth century. However, since the 1960s, a large number of investigations have been devoted to the phytocannabinoids and more recently to the endocannabinoids fields. Today, the pharmacology and therapeutic efficacy of cannabis preparations and Δ⁹-tetrahydrocannabinol (Δ⁹-THC) have been extensively reviewed (4–8).

The other important cannabinoid of current interest is cannabidiol (CBD). There has been a significant interest in CBD over the last few years because of its reported activity as an antiepileptic agent, particularly its promise for the treatment of intractable pediatric epilepsy (9). Other than Δ⁹-THC and CBD, tetrahydrocannabivarin (THCV), cannabinol (CBN), cannabigerol (CBG), and cannabichromene (CBC) are major isolates. During the late nineteenth and early twentieth centuries, pharma-companies produced and marketed numerous cannabis containing remedies in Europe and the United States. Merck, Burroughs-Wellcome, Bristol-Meyers Squibb, Parke-Davis, and Eli Lilly marketed various cannabis extracts and tinctures. However, due to numerous concerns about illicit/recreational use and availability of synthetic alternatives, cannabis was dropped from the British Pharmacopeia in 1932 and from the United States Pharmacopeia in 1941. These concerns led to national and international laws restricting/regulating the medicinal use and research of cannabis.

Currently, cannabis is considered the most widely used illicit drug in the world and therefore highly regulated in the USA at the federal level. A growing number of studies have recently reported that higher potency cannabis preparations are associated with adverse health outcomes, including elevated symptoms of cannabis use disorder, increased emergency room admissions for cannabis problems, higher risk of developing psychosis, and increased risk of relapse to psychosis (10). Increases in cannabis potency and the associated health effects are especially significant among adolescents who are more vulnerable to cannabis harms (11). Therefore, it is very important to monitor the potency the confiscated biomass and cannabis products available on the market as a measure of what is actually being sold and consumed by the public.

Several recent reports from different parts of the world such as Norway, Turkey, The Netherlands, England, France and Italy (12) shows that the potency of cannabis and cannabis related products are constantly increasing. This is consistent with our previous studies in the USA reported in 2021, 2016, 2013, 2010, and 2000 (12–16). In a meta-analysis performed on 21 different studies worldwide, containing 75 observations on mean Δ⁹-THC levels in herbal cannabis samples, revealed a consistent increase in cannabis potency worldwide over time (17).

In our last cannabis potency study, we reported that cannabis potency in the United States increased from ~4% in 1996 to ~14% in the year 2019 (13). In this article, we report cannabis potency trends in the United States over the last 10 years (2013–2022). For the purpose of this study samples collected from all over USA were categorized by region of seizure, namely; Western Region, Midwest Region, Northeast Region, South East Region, Southern Region as well as Alaska and Hawaii, in order to determine if there is a regional difference in the type of cannabis used in the different regions of the country.