Marijuana Overdose: Myth or Reality?

If you consume marijuana, you may have experienced unexpected effects that have played a dirty trick on you. Perhaps that has led you to wonder if you are overusing cannabis and if you could eventually die. In this article we try to discover the truth about whether it is possible to have a lethal overdose of marijuana, myth or reality?

Overdose is defined as taking an excessive dose of a substance, drug or medication that can lead to poisoning and death. According to the latest report by the EMCDDA (European Monitoring Centre for Drugs and Drug Addiction), an estimated 5,800 deaths from drug use were recorded in Europe in 2020.

Most of these deaths were caused by opioid overdoses such as heroin, but were also associated with prescription drugs such as oxycodone and tramadol. On the other hand, the use of stimulants such as cocaine and amphetamines also played an important role in deaths in recent years.

These figures vary by country, but we find similarities with the United States, where the main cause of overdoses are synthetic opiates, involved in 82.3% of overdose deaths. These data indicate that, in a country where marijuana is legal in many states and its use is common in a significant part of the population (about 20%), cannabis doesn’t stand out much in the annual overdose statistics.

But, is it possible to overdose on marijuana?

According to experts, overdosing for cannabis use is highly unlikely, given that the amount needed to cause a lethal dose would be enormous. Back in 1973, a study established the lethal dose of THC, the psychoactive cannabinoid of marijuana, between 225 and 3,600 mg/kg in laboratory rats. According to this data collected in animals, you would need to smoke a joint the size of a telephone pole (more than 12 kilos of marijuana) to make it lethal in a 60 kg person. This figure increased even more in later studies.

With these astronomical amounts, it is clear that marijuana overdoses should be at least uncommon. This doesn’t mean that cannabis doesn’t contain certain levels of toxicity, or that it is possible to take it in excess, since marijuana can cause negative effects that intensify with the amount consumed. These include lack of coordination, anxiety and paranoia.

Most people who overdose on cannabis are not at risk of dying from toxic changes in their normal body function. However, anyone who consumes excessive amounts can experience serious and potentially dangerous changes in their physical or mental well-being.

Why opioids cause lethal overdoses while cannabis doesn’t

Medical marijuana, as well as opiates, may also be prescribed to relieve pain due to its analgesic effects. To understand why marijuana doesn’t cause overdose, we must first understand what causes opioid overdoses.

Opioid overdose occurs when a person receives unopposed excessive stimulation, that is, without other stimuli to counteract it, from the opiate pathway found in our brain. This can lead to a diminution in that person respiratory drive, which can cause death.

This happens because opioids interact with receptors found in the part of our brain that controls breathing and, its stimulation can cause slow breathing. Many studies claim that cannabis doesn’t interfere with breathing because its cannabinoids, such as THC or CBD, do not interact with receptors in the part of the brain responsible for this function. Marijuana would act through other cell signalling pathways to exert analgesic effects without affecting this area.

However, studies have found cannabinoid receptors in regions of the brain that control breathing in rats. This research opens the door to a second possibility and, although the cannabinoids of marijuana were attached to these regions of the brain, they would not do so as strongly as opiates.

Even though much more research is needed, cannabis has proven to be a safer substance than opiates to treat pain. For this reason, studies are testing cannabinoids as a complementary pain treatment to reduce opioid doses, thus lowering patients’ risk of overdose.

Children marijuana overdose

Nevertheless, there are still many doubts to resolve on this issue. One of them being the cases of marijuana overdoses in children in the United States. In 2011, the case of a 14-month-old kid who was in a coma for two days after an accidental ingestion of hashish was published. The patient’s blood THC levels were very high but, fortunately, the child was able to recover when they decreased. 

While these cases are rare, they can occur among the youngest and so we must be careful if we keep marijuana at home and ensure that it is not within reach of children.

Risk of cannabis edible overdose

Cannabis edibles require special attention, as children and pets can eat them accidentally. Since cannabis edibles were legalised in the United States, this is one of the most frequent causes of cannabis overdoses in children.

But edible marijuana can also be a danger to consumers themselves, as there is an increased risk of poisoning. This happens because, while the psychoactive effects of smoking or vaping marijuana can be noticed within a few minutes, the effects of ingested cannabis can take between 30 minutes and 2 hours to appear.

During this time, and thinking that the amount that has been taken is insufficient, the consumer can ingest an excessive dose, ignoring its effects until it is too late, being able to experience dizziness, nausea, tachycardia or paranoia.

In addition, the effects of THC are more potent when metabolised through the liver. This occurs because, when digested, THC is transformed into 11-hydroxy-THC (11-OH-THC). This metabolite is very active and easily crosses the membranes that separate the bloodstream from the brain tissue, hence its intense psychoactive effect.

Therefore, we get a much more powerful version of THC that arrives very quickly to our brain, which provides an effect that seems more intense and lasting than the one obtained by inhalation. In fact, levels of 11-hydroxy-THC are typically higher when eaten compared to smoking. All this makes it very difficult to control the dose when you ingest marijuana and makes it easier to consume in excess.

So you know if you want to enjoy only the best of this plant, do not exceed the maximum portion, keep the edibles in a safe place and always control their cannabinoid content. To paraphrase Paracelsus, “the dose makes the poison” and no substance is completely harmless if ingested in large quantities. In fact, drinking too much water can kill you sooner than marijuana would.