Those who smoke a joint now and then often like to argue that alcohol is far more harmful to health than marijuana or hash.
Indeed, we’ve long known about the dangers of alcoholism. But as more and more places around the world move to legalize the recreational use of cannabis, more serious risks are becoming clear.
What damage does alcohol and cannabis do to health? Is a night of heavy drinking just as bad as getting stoned for a day? Here’s how scientists assess the risks.
Alcohol is a cytotoxin that quickly enters the entire body via the bloodstream. It alters the transmission of information in the brain, and larger amounts can lead to alcohol poisoning.
The hemp plant Cannabis sativa contains more than 60 cannabinoids, of which THC is classified as the strongest psychoactive substance. Throughout the body there are receptors to which the body’s own cannabinoids, but also THC, dock.
In general, the effects of alcohol are better researched. With cannabis there is the added difficulty that the THC content of the plants can be highly variable.
Acute negative effects
Both substances have a very rapid effect on the brain, typically reducing concentration levels and the ability to remember things. Alcohol is one of the most frequent causes of accidents in road traffic, but cannabis is also known to impair the ability to drive.
Alcohol increases the aggressive nature in some people – almost every third act of violence occurs under the influence of alcohol. Cannabis, meanwhile, has a relaxing and calming effect on many people, but it can also trigger feelings of paranoia and panic.
People who drink alcohol too often damage their health and reduce their life expectancy.
Many people only think of alcohol dependence. However, more than 200 diseases are known to be promoted or directly caused by any kind of regular alcohol consumption, says Ulrich John, a social physician at Germany’s Greifswald University Medical Centre.
These include many liver, cancer and cardiovascular diseases. Recent studies also refute the myth that alcohol in moderation has a generally positive effect. For example, the risk of breast cancer increases with three to six glasses of alcohol per week.
With cannabis, there are indications of a connection with diseases such as depression or testicular cancer. Several studies show that the risk of psychosis increases – especially if people start smoking it at an early age.
According to estimates by addiction researcher Jakob Manthey, about 5 per cent of all registered deaths are due to the consumption of alcohol.
However, it is plausible to assume that there are also deaths due to cannabis use, says the psychologist.
In 2019 in Germany, for example, at least 52 people are known to have died in traffic accidents in which cannabis or other drugs played a role. In addition, more than 80 per cent of users smoked cannabis together with tobacco, exposing themselves to an increased risk of cancer.
Risk for youths
Both alcohol and cannabis use in adolescence damage brain development.
Child and youth psychiatrist Rainer Thomasius warns of brain damage even by occasional cannabis use. Even at the age of 18, the brain is not yet fully developed, says the head of the German Centre for Addiction Issues in Childhood and Adolescence at the UKE. There is a risk of reduced intelligence, attention and concentration.
According to a study, the risk of developing psychosis for the first time increases three to five times with daily cannabis use, depending on the THC content.
Early psychosis detection centres are necessary, says Andreas Heinz, director of the Department of Psychiatry and Psychotherapy at the Charite Hospital in Berlin. “If a society wants to allow itself to use a drug, then it has to take care of those who fall under the radar.”
In adolescence, the risk of ending up in hospital with alcohol poisoning is greater. Those who start drinking at an early age often drink too much later on, become dependent or suffer from secondary diseases such as fatty liver at the age of 40 or 50.
About 2.5 per cent of the world’s population – 147 million people – consume cannabis, according to the WHO. That’s even less than the number of people who die every year as direct or indirect result of alcohol.
“Alcohol consumption contributes to 3 million deaths each year globally as well as to the disabilities and poor health of millions of people,” the WHO says. “Overall, harmful use of alcohol is responsible for 5.1 per cent of the global burden of disease.”
While alcohol and tobacco consumption is declining among young people in many countries, smoking cannabis is becoming more popular, according to surveys.
Medical experts estimate the addictive potential of both substances to be similar. However, in contrast to cannabis, alcohol withdrawal showed particularly severe physical symptoms.