Health experts oppose legalisation and deregulation of cannabis for personal use

Recently, there have been a number of statements and messages portraying cannabis use as a normalised behaviour rather than a health risk. However, experience from other countries where cannabis has been legalised, such as some US states and Canada, shows the opposite. Cannabis use increases because of the general belief that cannabis preparations are harmless or even beneficial.

Thus, based on the experience of countries that have chosen to deregulate cannabis in recent years, we know that as availability increases, cannabis use increases, and that in addition to increasing duration of use, users are switching to products with higher THC content. It is also already clear that the illicit cannabis market is not disappearing at the expense of cannabis legalisation.

It should be reiterated that cannabis is an addictive drug. About one in five people who use cannabis has a substance use disorder. This risk increases with earlier initiation and more frequent use. It is estimated that one in three adolescents who have used cannabis at least once a week is dependent on it, which is a more severe form of cannabis use disorder.

Cannabis use during pregnancy may have adverse effects on the foetus

Cannabis can affect the baby intrauterine when mothers use cannabis with THC for various purposes during pregnancy. In addition to an increased risk of low birth weight, anaemia and the need for intensive postnatal care, children have been shown to have significant cognitive effects such as impulse control problems, attention problems and visual memory deficits.

Early cannabis use may lead to more severe mental disorders

Cannabis is the most commonly used illicit psychoactive substance among adolescents, most of whom use or abuse cannabis for non-medical purposes. The active ingredients THD and ECB are involved in the complex action of endocannabinoids and endogenous substances that influence the development of neurons and their connections, e.g. BDFN, NGF.

Because of these recognised effects on biological processes, regular cannabis use during adolescence may have an impact on brain or cognitive function. Research confirms that adolescent cannabis use, especially heavy use, is associated with poorer cognitive functioning, learning difficulties, lower academic achievement and socio-economic consequences. Moreover, early onset of cannabis use/abuse has been shown to be associated with lower earnings and work engagement in early adulthood. There is no scientific evidence that cannabis use has a beneficial effect on the prevention or treatment of mental disorders. On the contrary, cannabis use has a negative impact on adolescents’ mental health.

Early initiation of cannabis use and frequent and regular use have been shown to have a significant impact on the development of serious mental disorders in childhood, adolescence or adulthood. Cannabis use with THC is associated with the occurrence of acute psychotic episodes and the development of chronic psychotic disorders such as schizophrenia. Regular cannabis users are at increased risk of developing dependence on other psychoactive substances, anxiety and mood disorders. Adolescents often use cannabis for self-medication, which can lead to untimely seeking of professional help and worsening of health conditions. Adolescents who use cannabis regularly have more suicidal thoughts and actions than those who do not use cannabis.

The harmful consequences of misleading and uncritical messages about cannabis are also reflected in a decline in risk perception or even approval of cannabis use among adolescents, which increases the risk of use. Data confirm that the proportion of adolescents who perceive cannabis use as a health risk has decreased in recent years. According to internationally comparable data, Slovenia already has an unenviable record in terms of the prevalence of cannabis use among adolescents compared to other European countries. 17.6% of Slovenian adolescents are classified as high-risk users. The prevalence of cannabis use among vulnerable adolescents is even higher. Almost half of adolescents (47.3%) perceive cannabis as easily accessible. Accessibility and the low perceived risk associated with cannabis use are key factors influencing the prevalence of cannabis use among adolescents.

Five times higher risk of heart attack in the first hour after cannabis use

Cannabis use usually causes rapid heart rate, palpitations and tightness in the chest, and can also lower blood pressure, which may be manifested by dizziness and temporary loss of consciousness. In about 5,000 adults who had smoked cannabis occasionally in their youth, no increased incidence of cardiovascular disease, the main cause of which is atherosclerosis of the blood vessel (e.g. coronary heart disease and stroke, was found during a 30-year follow-up in adulthood. However, it was found that cannabis can cause exacerbation of chronic stable angina and the onset of ischaemia or low-exertion angina in patients with chronic stable angina.

When cannabis use increases heart rate and blood pressure, and thus the heart’s need for oxygen, coronary heart disease patients may experience a lack of oxygen to the heart muscle. A study that followed thousands of patients admitted to hospital with heart attacks found that cannabis use was associated with a 5-fold increased risk of heart attack in the first hour after cannabis use. In addition, the mortality rate of cannabis users admitted to hospital with an acute heart attack was shown to be several times higher than that of patients who did not use cannabis. For daily cannabis users, the risk of heart attack increases by a few percent per year.

Cannabis poisoning on the rise, most common among the most vulnerable

According to the Centre for Clinical Toxicology and Pharmacology at the University Medical Centre Ljubljana (UMCL), cannabis poisoning – both intentional and unintentional – is on the rise. Signs and symptoms of cannabis poisoning that prompt users to seek medical help may include disturbed consciousness (from excessive drowsiness to unconsciousness), dizziness, light-headedness and wandering, nausea, vomiting, severe agitation, anxiety and panic attacks, pseudo hallucinations, psychotic episodes, seizures, rapid heart rate, chest pain, blood pressure fluctuations, heart rhythm disturbances, heart attacks.

Cases of severe and irreversible lung damage associated with the use of electronic vaporisers for the consumption (vaping) of cannabis preparations have been described.

Poisoning is more common in the most vulnerable groups, such as children, adolescents, the elderly and the chronically ill. In children, poisoning is manifested by dullness, lethargy, hyperactivity, irritability, possibly even unconsciousness and seizures.

In older chronic patients, cannabis intoxication is most often manifested by a more severe impairment of consciousness, slowing down, often with restlessness, confusion and/or cardiovascular side effects. This can also be life-threatening, as these patients often have pre-existing cardiac conditions such as heart rhythm disturbances, ischaemic or structural heart disease.

Risk of car accident 2 to 3 times higher under the influence of THC

In recent years, occupational, transport and sports medicine doctors have observed an increased prevalence of cannabis use among the working population, as reflected in an increase in the number of positive tests at screening, an increase in the number of employer referral for suspicion of working under the influence of cannabis, and an increase in the number of subjects self-reporting use of cannabis. Cannabis use among employees can have a negative impact on work capacity due to problems with memory, concentration, motor coordination and reaction time, contributing to both reduced performance at work and increased risk of work-related injuries.

Cannabis use also reduces psychophysical fitness to drive, which increases the risk of road accidents. Experience from other countries where legislation has been changed to facilitate access to cannabis shows that such changes increase the presence of THC in drivers. In some countries, this has been reflected in a deterioration in road safety and an increase in road accidents, including fatalities (e.g. Colorado, USA).

Cannabis-impaired driving is mainly characterised by a reduced ability to maintain a stable position on the road, difficulties in following traffic at junctions and difficulties in controlling the vehicle, which are particularly pronounced in challenging situations. Young drivers are a particularly high-risk group because, in addition to their lack of driving experience, they often misjudge the safety of driving under the influence of THC or their ability to compensate for the negative effects.

Use of cannabis for medicinal purposes only under medical supervision and in rare cases

The use of cannabis for medicinal purposes has been allowed in Slovenia for many years. It started in 2014 with the authorisation of the medical use of cannabinoids (compounds found in cannabis), and since 2017 it has also been possible to use medical cannabis. Other cannabinoid-based medicinal products are also available to patients on prescription, the cost of which is covered by the Health Insurance Fund of Slovenia.

Cannabinoid treatment is prescribed by a physician based on medical evidence applied in three areas:

• In oncology for the adjunctive symptomatic treatment of nausea, vomiting and pain in palliative care patients.
• In neurology for the adjunctive symptomatic treatment of spasticity and neuropathic pain in multiple sclerosis.
• In paediatrics for adjunctive symptomatic treatment of patients with rare, severe forms of epilepsy.

It should be noted that cannabinoid treatment is complementary and symptomatic, meaning that it cannot change the course of the disease or cure it, as is often mistakenly imagined by patients or their relatives. In fact, in recent years, there has been a growing gap between lay beliefs about the efficacy and safety of cannabinoids for medical purposes and the views of the medical profession, based on clinical research in this field.

Based on past experience, doctors rarely choose cannabis treatment, as more effective and safer medicines are available for most conditions, and development of these medicines is steadily increasing.

For other conditions – such as chronic inflammatory bowel disease, atopic dermatitis, acne, psoriasis, skin cancer, anxiety, burnout, insomnia and various autoimmune and rheumatic diseases – there is no scientific basis and doctors advise against the use of cannabinoids and cannabis.

National Institute of Public Health

Institute of Oncology Ljubljana

Clinical Institute of Occupational, Traffic and Sports Medicine, UMCL

Centre for Clinical Toxicology and Pharmacology

Department of Child Psychiatry, Division of Paediatrics, UMCL

Association for Child and Adolescent Psychiatry – ZOMP

Coordination of Centres for the Prevention and Treatment of Drug Dependence