chemical structure of psilocybin molecule, the psychedelic compound in magic mushrooms (shrooms)

More than 180 psilocybin-containing mushrooms species are found all around the world. When eaten these can induce hallucinogenic/psychedelic effects. The key ingredient found in these mushrooms is psilocybin. Psilocybin is a so-called pro-drug which means that it is converted in the body to psilocin which is the chemical with the psychoactive properties. Additional chemicals commonly present in minor amounts include psilocin itself, baeocystin and norbaeocystin although the extent to which these contribute to the overall effects is unclear. Psilocybin mushrooms are often called magic mushrooms or shrooms.

The small and potent liberty cap mushroom (Psilocybe semilanceata) is probably the most common and widespread species found in Europe. Other species occur in the wild, and Psilocybe cubensis is cultivated indoors.

Picking mushrooms

The risks involved in picking your own are getting the right species. Liberty caps are very similar to many other small grassland fungi that will not make you trip, could make you sick or possibly harm you. Other larger psilocybin mushrooms that grow on wood and in forests can be confused with mushrooms that kill or leave you needing organ transplants. It is risky to pick magic mushrooms, especially without the guidance of someone with experience.

Buying and/or receiving mushrooms

The risks of buying mushrooms are the same as buying any illegal drug; the market is unregulated so it is possible that these products could be spiked with synthetic substances of unknown origin, quantity and quality. Unprocessed fresh or immediately dried mushrooms are not known for being adulterated, though they can be a bit mouldy and give you an upset stomach. Any further processing (e.g. powdered and put into capsules, or food) gives more opportunities for adulteration, or getting the dose wrong.

Consuming mushrooms

It is important to recognize that natural products tend to vary in strength even within the same species and across locations. Psilocybin mushrooms are consumed in many ways, fresh or dried, for example brewed into a tea or alcoholic beverage and drunk, put into food, ground up and swallowed. As mushrooms are almost entirely water, a dose of fresh mushrooms will weigh something like 10 times more than the same dose dried. Microdosing psilocybin has become increasingly popular but there is very little research into microdosing at this stage.

Psilocybin and psilocin are psychedelic tryptamines. The chemicals have a structure very similar to the structure of serotonin, a chemical messenger with important roles in our brains and digestive systems. Because of this similarity, psilocin can bind to receptors in the brain that are meant for serotonin. Binding and activation of serotonin receptor sites correlate with the manifestation of psychedelic effects and one important receptor sub-type is the 5-HT2A receptor.

Although our understanding is incomplete, recent studies have given new insights into how psilocybin works. Notably, it is thought that psilocybin works by suppressing parts of the brain that filter out information from a person’s senses. This would cause more sensory information to reach a persons consciousness, causing hallucinogenic effects and changes in perception.

Psilocybin mushrooms produce changes in consciousness mood, thought and perception that people call a ‘trip’, or a ‘psychedelic experience’. Especially at higher doses the effects can be extremely intense and indescribable. Perhaps the most important consideration someone should make before deciding to take this drug, especially at moderate or high doses, is whether they are likely to find the experience of losing grip on reality distressing. Everyone’s experiences of mushrooms are unique to them, so what may be an easily manageable dose for a friend may be too much for you.

Psilocybin mushrooms can cause people to think about things in peculiar ways, they sometimes make people feel euphoric, and can cause visual and auditory hallucinations. Hallucinations can be subtle or all-encompassing. Colours may change in tone and intensity, surfaces may move, colourful fractal patterns can form and with high enough doses, objects morph into other things and users may experience encounters with imaginary places and people. There can also be changes in the perception of time, with minutes potentially feeling like hours and vice versa. Acting and talking normally are likely to become impossible above very small doses. The experience can be spiritual and some people rank their experiences with mushrooms among the most personally important times in their lives. Equally, the experience can be just a bit of interesting fun, or can be regrettable.

Possible physical side-effects include nausea and stomach discomfort. Your pupils get very large and you may feel heavy and clumsy. The appearance of delayed headaches can also occur following ingestion of magic mushrooms which may persist for up to 2 days. After tripping, you may feel wiped out and in need of rest. The more you take and the bigger the trip, the greater the chance of unpleasant side-effects and after-effects.

The psychedelic experience is quite often overwhelming, frightening or unpleasantly disorientating, at least for passing moments. Trips which are terrifying throughout are much less common but they do happen. The risk of horrible psychological effects gets higher with increasing dosages.

It can take between 10  to 60 minutes after eating psilocybin mushrooms before the effects kick in. A moderate dose will wear off after about 4 hours, although the tail-end of the experience can be long-lasting, with some lingering effects of a strong dose continuing for hours, so driving could still be dangerous and working difficult after a trip. It is important to note that the strength of psilocybin mushrooms is hugely variable, and as with all drugs, different people can respond very differently to the same dose.

There is some evidence to suggest that psilocybin, even in doses too small to produce hallucinogenic effects, gives relief to people suffering from chronic cluster headaches, one of the most painful conditions that exists. However, there is a need to conduct appropriate clinical trials to establish whether psilocybin is indeed useful as a treatment.

Additionally, the use of psilocybin alongside psychotherapy is increasingly investigated for the treatment of some psychiatric problems such as obsessive compulsive disorder and depression. Psilocybin therapy is currently being researched by research groups around the world. More research into psilocybin therapy is needed to investigate these potential medical uses further. Attempts to use magic mushrooms for self-treatment of any condition could be risky and is not advised.

For more detailed information on the medical applications of psilocybin, based on clinical trials, click here

It is near impossible to take a dose of psilocybin mushrooms that is physically toxic to your body or brain. Psilocybin does strongly affect judgement and coordination however, so doing something like driving whilst under the influence of psilocybin would be very dangerous and illegal. Whilst there are many urban myths about bizarre deaths on hallucinogenic drugs, people do very occasionally get injured or killed because of the effects of the drug on their behaviour. Someone taking psilocybin mushrooms should plan ahead to make it impossible that they might end up around roads, cliffs or anywhere where they could have a serious accident.

Psilocybin can induce states of confusion, misery, agitation and fear. Negative experiences induced by hallucinogenic drugs are often referred to as ‘bad trips’. A point here is that assuming that a trip as a whole is going ‘bad’ at the first sign of an unpleasant effect could be a self-fulfilling prophesy. Bad or at least overly intense, difficult moments during strong trips are quite common but usually pass or can be overcome. Having said that, there is a risk that high doses of magic mushrooms can cause disastrous, prolonged and traumatic effects called a ‘psychedelic crisis’, though this is not common.

The risk of someone suffering unpleasant effects is increased if the drug is taken without preparation or if it is taken in a less-than-ideal setting, like a busy, loud party full of strangers. There is also a risk of making mental illness worse or even triggering it if the person taking the drug has a pre-existing vulnerability to this. However, the risk of long-term psychological disturbance is low.

HPPD and ‘flashbacks’

HPPD is a very unusual and poorly understood harmful effect of having taken hallucinogenic drugs. There are few or no good quality formal accounts of psilocybin causing HPPD (LSD is more commonly the cause) but it likely to be possible, and could go unrecognised.

It is most often experienced as re-appearance of some of the effects experienced during the previously occurring hallucinogenic drug experience after some time without the drug. In most cases HPPD follows a traumatic hallucinogenic drug experience (‘bad trip’). In some cases, sufferers may feel detached from normality or the world.

HPPD has been reported occasionally as longer-lasting, though complete or partial recovery usually occurs after weeks or months. Lingering HPPD has been associated mostly with LSD rather than psilocybin, and often involves higher doses and drug combinations. This kind of HPPD may occur in people with underlying psychiatric conditions or genetic vulnerabilities, but the evidence is very incomplete.

Any history of mental health problems could increase the chance that the trip is unpleasant or traumatic, and the more serious risk that there are lasting harms (see also the information provided in the LSD entry). If you have or have ever had schizophrenia or a psychotic episode, tripping could trigger a relapse or worsening of the condition. As mentioned before, external conditions (the ‘setting’, see below) can also have a tremendous impact on the nature of the psychedelic experience which means that an obnoxious environment (e.g. people or location) can increase the risk of inducing unpleasant or horrible trips.

Psilocybin mushrooms should not be taken by those who are on psychiatric medications in order to exclude any potential for adverse drug-drug interactions.

People do not seem to become addicted to psilocybin mushrooms. Although some people take them quite regularly, they are unlikely to struggle with stopping taking them if they feel that the drug is causing them problems. Temporary tolerance discourages people from taking mushrooms repeatedly over a short period, as a dose that on one day produced strong effects may have no effects if repeated the next day.

Harms such as HPPD seem more likely in people who use drugs regularly and heavily.

Magic mushrooms have relatively low risks to physical health compared to many other drugs, because they are not considered addictive and are rarely used regularly. However, tripping on a psychedelic drug has the potential to produce overwhelming and intensely unpleasant experiences.

Being prepared

It is difficult to measure doses of mushrooms reliably due to variations in psilocybin levels and it is impossible to fully imagine the nature of effects if you have not tried them before. There is an argument to suggest that they should be avoided if the user is not prepared to have a potentially overwhelming experience. Many people choose not to take psychedelics because they do not want to feel out of control.

The effects that psychedelics can induce are normally only controllable to some extent but proper planning is advisable. Whilst many people think that the use of powerful and controlled drugs can never be considered entirely responsible and well-judged, people who are informed about the factors which affect the mood of a trip are certainly less likely to experience unpleasant thoughts and effects.

Set and setting

A useful way of remembering the factors that help determine whether a trip is rewarding or nightmarish is the concept of ‘set’ and ‘setting’.  A person’s ‘set’ (or mind-set) includes their mood, disposition, thoughts and expectations. A person’s ‘setting’ is the specific place and social situation in which they take the drug. If an anxious and miserable person accepts magic mushrooms without having planned for this at a chaotic party where they know and trust no-one, then their trip may lead to disastrous experiences. Taking hallucinogens in a calm, familiar place, with someone you trust to be your sober ‘trip-sitter’ is far less likely to be something regrettable.

Having a sitter

Psychedelic drugs trigger a complex range of altered states of consciousness which can make people highly suggestible, especially in the presence of other people. This also means that their ideas strongly influence the way that they perceive the world. For example, once the thought has occurred that they might be dying, they may see their skin appearing to go grey and blotchy. However, this suggestibility is not necessarily all bad; it means that a sober helper, (sometimes called a ‘trip sitter’) can often successfully reassure them, or distract them with a change of scene or showing them something. It is essential to remind someone who is showing signs of beginning to have problems that what they are feeling is not real, and that they have taken a drug which will wear off. Reassuring comments and gestures can be helpful.  Have a discussion before you begin as to what to do if things do not go smoothly.

Are you sure you are not taking a poisonous mushroom by mistake?

Certain types of psilocybin mushroom look like some very poisonous mushrooms. If you are going out to find your own mushrooms then you have to be extremely careful that you are not accidentally picking and eating a poisonous mushroom by mistake.  Be very cautious about following any guidance from the internet; remember for example, that every country has its own species of mushroom. Some mushrooms can kill you or make you very ill, so if you are unsure about a mushroom you should not eat it. Symptoms of liver failure caused by mushroom toxicity may not appear until a few days later.

Are fly agaric mushrooms (Amanita muscaria) psilocybin mushrooms?

No. Fly agaric mushrooms (the fairytale toadstools with white spots on red) belong to a different family and should not be confused with psilocybin-containing mushrooms. Rather than psilocybin, the key chemicals associated with the psychoactive effects include ibotenic acid and muscimol. Effects can include twitching, drooling, sweating, dizziness, vomiting and delirium, very unlike the fairly mild physical effects of psilocybin mushrooms. Fly agaric mushrooms do not appear to be a popular recreational drug. In the UK, when the sale of fresh psilocybin mushrooms became controlled, some shops started selling dried fly agaric mushrooms as a non-controlled alternative. However, there is a risk that these type of products might contain a range of added substances, especially when powdered samples are involved. The fly agaric and commercially available products of that nature should not be considered a legal alternative to psilocybin mushrooms as their effects and risks are very different.

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