Researchers have uncovered the earliest known evidence of cannabis use, from tombs in western China. It is believed that cannabis was being smoked at least 2500 years ago, and that it may have been associated with ritual or religious activities. The traces of the drug were identified in wooden burners at Jirzankal Cemetery, high up in the Pamir Mountains. The cannabis had high levels of the psychoactive compound tetrahydrocannabinol (THC).
Cannabis plants have been cultivated in East Asia for their oily seeds and fibre from at least 4000 BC. The ancient cultivators realised that the plant had two main properties. When the flower buds were discovered to have psychoactive effects, cultivators began separating the plants to isolate their ‘medicinal’ characteristics: these plants closely resemble today’s marijuana plants. The other variety of the plant was bred to be tall and durable and became what we now call industrial hemp. The industrial hemp plants tend to produce high levels of cannabinoid (CBD), while producing low amounts of THC. Conversely, the marijuana plant produces high THC levels and low CBD levels.
The international team behind the latest study reported in Science Advances  think that people were deliberately breeding plants with higher levels of THC and burning them as part of funeral rituals. This is the earliest clear evidence of cannabis being used for its psychoactive properties.
Drug testing for cannabis
The scientists used gas chromatography–mass spectrometry (GCMS) to isolate and identify compounds preserved in the burners. The chemical signature of the isolated compounds was an exact match to the chemical signature of cannabis. The findings tally with other evidence of cannabis from burials further north, in the Xinjiang region of China and in the Altai Mountains of Russia.
Nicole Boivin, Director at the Max Planck Institute for the Science of Human History in Jena, Germany, said: “The findings support the idea that cannabis plants were first used for their psychoactive compounds in the mountainous regions of eastern Central Asia, thereafter spreading to other regions of the world.”
Today, cannabis is highly detectable and can be tested for in urine, saliva, hair as well as nail clipping samples. AlphaBiolabs’ range of tests for cannabis vary in their windows of detection so recent or chronic use can be established. In addition, ingestion as opposed to environmental exposure can be discerned.