Vilnius University, Toxicology Centre in Clinic of Anaesthesiology and Intensive Care, Vilnius, Lithuania
Recent changes in some countries in marijuana legalising for medical or recreational use mean that cannabis is obtaining growing importance for all society and public health. Despite warnings about health risks, many people see cannabis as a harmless substance that, unlike alcohol or tobacco, might even be good for your physical and mental health. There is scientific evidence that regular use of the cannabis increases the dose-related risk of developing psychotic episode, schizophrenia, depression and anxiety. However, does cannabis cause these illness or do these people just use it as a self-medication? Over the past decade research has confirmed the link between cannabis use in adolescents and later mental health problems in patients with a genetic vulnerability – not everyone who uses cannabis in young age develops a psychotic illness. Recent research has proved that people who use marijuana and carry a specific variant of the particular gene, which affects dopamine pathways, are at increased risk of developing psychosis. The amount of the main psychoactive ingredient Δ-9-tetrahydrocannabinol varies from 1% in naturally growing plants up to 20% in newer indoor growing strains. Another important cannabinoid – cannabidiol (up to 4%) counteracts the anxiety caused by THC. Most of the cannabis produced in Europe is cultivated indoors and may have a high THC concentration, but contains very low levels (≤0.1%) of CBD. It might be the reason why cannabis in the past was not thought to be addictive, but recent data suggests that it can be, especially if used regularly. Some researches suggest that cannabis use is likely to precede the use of other psychoactive substances.