Hallucinogen Addiction Symptoms and Warning Signs

Hallucinogens are any of a wide variety of substances – not necessarily related to each other chemically – which cause hallucinations, altered perceptions, changes in thoughts and emotions, and experiences in consciousness which are different from the norm.

While some hallucinogens have been used by human beings for a broad range of purposes – including as part of spiritual/religious practices and rites – since long before historical records began, and a small number are used medically (with support growing for more research into their therapeutic properties), in general most hallucinogens are banned in the majority of countries worldwide; however, they are widely used recreationally and have influenced many of the world’s most famous artists, authors and musicians, as well as other public figures.

Generally speaking, for a drug to be considered a hallucinogen its most obvious effects (predominating over others) should be the changes to perception and consciousness mentioned above; there is, however, no strict rule governing which substances should and should not be considered hallucinogens and the interpretation may differ from one jurisdiction (or even one doctor) to the next.


The three most prominent types of hallucinogens are psychedelics (changes in visual and/or auditory experiences and consciousness); dissociatives (distorted senses and a feeling of detachment from oneself and one’s surroundings); and deliriants (a state – often unpleasant – of delirium and loss of control).

Easily the most commonly encountered dissociative in the UK is ketamine (“K”); others include PCP (“angel dust”) and the plant Salvia divinorum. Although there are a large number of different deliriants, due to the frequently unpleasant nature of the hallucinations they produce and the fact that some are extremely toxic, they are rarely taken in this country: examples include belladonna, Mandrake, datura (all of which have been associated at various times with witchcraft), atropine and scopolamine.

Key Facts About Hallucinogens

As noted above, hallucinogen use has been part of human activity since prehistory, but outside a limited number of relatively isolated societies, some religious sects and cults, and a handful of Western adventurers, their use in modern times was comparatively limited until the rise of the hippie “counterculture” in the 1960s.

The synthesis of LSD by Albert Hofmann in 1938 from the fungus ergot and his famous accidental discovery of its hallucinogenic properties in 1943 attracted the attention of the USA’s Central Intelligence Agency (CIA), which tested the drug (almost invariably without their knowledge) on an unknown but large number of servicemen and students; some of these later began producing the drug themselves, launching the recreational use of psychedelics into the mainstream.

Since these remarkable developments, hallucinogens have become widely established around the world as recreational drugs and have had a significant cultural impact. In the UK as elsewhere, they are illegal substances – most categorised as Class A controlled substances (the most serious classification) with potentially severe sentences for possession and/or supply. Nevertheless, while not enjoying the popularity of some other illegal drugs, hallucinogens retain a substantial fan base; the Crime Survey for England & Wales showed that in 2015 approximately one in every 200 people aged 16-24 is a user of LSD (the most popular hallucinogen in the country).

Many hallucinogens are not usually considered to be directly physically harmful (though, on the other hand, some deliriants can be fatal above a certain dosage) though users are at much greater risk of damaging or fatal accidents, and of behaviour while under the influence which can cause harm or death to themselves and/or others. However, the implications for a user’s mental health can be profound, with some drugs posing a risk of permanent life-changing effects even after only one dose.

Signs and Symptoms

Because of the great variety of drugs coming under the “hallucinogens” banner, and the unique nature of any one individual’s reaction to each of those drugs, at small dosages (which of course vary hugely from drug to drug) it’s impossible to compile a “checklist” of symptoms that would allow an observer easily to identify which specific hallucinogen a person may have taken – or, indeed, to say for certain that they may have taken a hallucinogen rather than a drug of a different kind. On the other hand, as dosages increase a user’s behaviour can become so abnormal that it may seem impossible to conclude anything other than that they are under the influence of hallucinogenic drugs!

Whilst bearing in mind that some of these symptoms may indicate the use of substances other than hallucinogens and that some could be indicative of serious mental health issues rather than drug abuse, some signs to look out for include:

  • Dilated pupils
  • An inability to focus either visually or conceptually
  • Slow, slurred, incoherent and/or nonsensical speech
  • Manic laughter
  • Confusion
  • Insensitivity to pain
  • Paranoia
  • Panic
  • Terror
  • Synaesthesia (“mixed senses”, ie “seeing” sounds, “tasting” colours etc)
  • Very limited spatial awareness
  • Aggression
  • Intense fascination with mundane items
  • Speaking or otherwise attempting to communicate with inanimate objects and/or empty space
  • Extremely volatile mood swings
  • Wetting/soiling oneself
  • Self-harm
  • Intense scratching

While many hallucinogens are consumed orally, there may also be evidence in the form of paraphernalia including smoking materials.

Long-Term Effects

The long-term effects of hallucinogen consumption vary considerably from one substance to another. In many (but by no means all) cases, there are limited physical effects; however, the psychological consequences can be extreme, life-changing and permanent.

Physical Effects

Because of their prohibited status and the clandestine nature of much of their consumption, research into the long-term physical effects of many hallucinogens has been somewhat limited. In most cases, the consensus is that there are few if any physical effects of any duration: the physical dangers are mostly related to the greatly increased risk of accidents and self-harm that hallucinogen use entails.

However, some hallucinogens certainly do present long-term physical challenges: ketamine abuse, for example, can cause severe damage to the bladder (in some cases requiring its removal) while certain deliriants can affect the kidneys and liver (as well as potentially poisoning the user). Anyone using any hallucinogen regularly should consult their GP about possible long-term ramifications.

Effects on Mental Health

Hallucinogens can cause incalculable damage to a person’s mental wellbeing even after only one dose. Stories of “acid casualties” (people whose personalities have been permanently altered by LSD) are, unfortunately, not simply urban legends; in some cases the consumption of a dose much greater than that intended leads to permanent psychosis and other serious conditions including hallucinogen persisting perception disorder (HPPD), or “flashbacks”.

If a hallucinogen user has a “bad trip” (a catch-all term for a deeply unpleasant hallucinogen experience) the resultant trauma can have long-term consequences in the form of PTSD and behavioural changes. Any hallucinogen abuse can contribute to depression, anxiety and a feeling of detachment from hitherto pleasurable realities. Memory loss and cognitive impairment can also result from even relatively minor use.

Next: Detox from hallucinogens, withdrawal and treatment options

Hallucinogen FAQ

Is LSD addictive?

LSD is not considered an addictive drug in the same way as substances such as heroin and alcohol, in that it does not create a physical dependency. It is relatively easy to build up a tolerance to LSD – whereby a user requires ever-increasing dosages to produce the desired effects – but a cessation of use will not produce withdrawal symptoms: in other words, someone should be able to stop using LSD at any given time without experiencing any physical consequences.

However, it is possible to develop a degree of psychological dependency upon LSD – which will become more problematic the longer a person takes the drug, and which may require professional treatment. If a user begins to associate the effects of LSD with a happiness or contentment which they do not find in “normal” daily life, they may find themselves striving to spend as much time as possible under the influence,

Can LSD abuse damage your brain?

People under the influence of LSD, or suffering from depression or psychosis associated with LSD consumption, can also engage in a variety of risky and abnormal behaviour which can have profound consequences for the brain, leading to accidents (for example falling), injuries sustained as a result of violence, exposure to excessively high or low temperatures

(spending too much time in hot sunlight or freezing conditions) or even intentional self-harm. Another prominent risk is that of combining LSD with other drugs: a person high on LSD may find it impossible to measure the appropriate dosage of another substance and may end up consuming vastly more than intended, which can have directly damaging effects upon the brain (as well as greatly increasing the risk of seizure and accidental injury).

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