Cannabis is the most widely used drug. in recent years, interest in cannabis has grown significantly. over the last decade, the number of cannabis users worldwide has increased by almost 21%, reaching approximately 219 million people in 2021. Can- nabis cultivation covers practically all regions of the world. In recent years, 151 countries have reported cannabis cultivation, both outdoors and indoors. The increased growth of the latter is particularly observed in North America and Europe. Global data shows that in 2021, 5,226 tons of marihuana and 2,014 tons of hashish were confiscated. an increase in seizures of can- nabis products is observed in Europe and Poland. Another trend concerns the increasing content of the psychoactive substance Δ⁹-tetrahydrocannabinol (Δ⁹-THC) in cannabis plants. According to UNODC data, over the last 25 years there has been a 4-fold increase in the content of Δ⁹-THc in cannabis. over the last decade, the average content of Δ9-tetrahydrocannabinol in marihua- na seized in europe has increased approximately twice, and in hashish three times.

The aim of this work is to assess potential changes in the content of the main psychoactive ingredients in cannabis in Poland in the last decade (2012–2022), based on expert opinions developed by the Institute of Forensic research in Kraków. The conduct- ed analyses confirmed the trends observed around the world. in the last ten years, the number of cases in which the drug-type cannabis was detected increased from 5.3% to 68.4% of total number of illicit drug cases examined for the presence of narcotic drugs, psychotropic substances and new psychoactive substances. an increasing trend in the content of Δ⁹-THC in the drug-type cannabis was also noted. over the last decade, the average total content of Δ⁹-THC increased almost three times and in 2022 reached 12%. This is due to the growth of cannabis cultivation in Europe, carried out using the technique known as sinsemilla, genetic modifications, as well as the appearance on the market of the feminized cannabis seeds.