The effects of psychedelics on language

“To be shaken out of the ruts of ordinary perception, to be shown for a few timeless hours the outer and the inner world, not as they appear to an animal obsessed with survival or to a human being obsessed with words and notions, but as they are apprehended, directly and unconditionally, by Mind at Large – this is an experience of inestimable value to everyone and especially to the intellectual.”

That experience was Aldous Huxley’s mescaline trip described in The Doors of Perception. Mescaline, like LSD (lysergic acid diethylamide), DMT (“the spirit molecule”), and psilocybin (the substance contained in magic mushrooms), is a hallucinogenic drug (or psychedelic) that alters the consumer’s perception of self and the environment, by triggering visual/auditory hallucinations, a distorted sense of time. Psychedelics are serotonergic, which means that they act on the neurotransmitter serotonin (5-HT). Though hallucinations are the most salient effect, as a linguist I’m interested in the influence of these drugs on verbal behavior.

LSD is the most researched psychedelic at the moment, mostly for its therapeutic effects. It was synthesized in 1938 by the Swiss chemist Albert Hofmann, but only in 1943 he discovered accidentally (!) its psychedelic properties, as he was biking home from his lab after tasting his discovery. (In memory of that first LSD trip we celebrate Bicycle Day on April 19th!).

Research on the effects of LSD on language shows that it does not impair language comprehension (Dahlberg, 1974), but it does alter language production in several ways.

People under the effect of LSD speak less and slower (von Felsinger et al., 1956; Lenard et al., 1956; Jaffe et al. 1972), and may be repetitive, but use more complex (Aaronson, 1955) or new words (a higher type-token-ration). They also tend to speak more in the first person and present tense (Fink et al., 1960) and to use defensive language (e.g. personal statements, less explanations) (Natale 1979). It’s worth noting though that the language patterns might be influenced by factors such as language, cultural background, goals, and expectations of the participants (Fink et al., 1960). Consumers also seem to use more figurative language (e.g. idioms, expressions, metaphors, wordplay) (Natale et al. 1978).

(Linguistic) creativity on psychedelics is linked to the spread activation of semantic networks (Spitzer et al., 1996; Family et al., 2016), a kind of mind map which represents semantic relations between concepts, so if the activation spread, it means that you “jump” some networks and associate more distant concepts. This effect has been found with LSD and psilocybin. How can we test this? With psilocybin, participants were first given a lexical decision task, where they were shown strings of letters and had to decide whether these were meaningful words or not (e.g. hukolp, master); in the second part, participants were presented pairs of words that were closely related (e.g. black-white), indirectly related (e.g. lemon-sweet), and unrelated (e.g. cloud-cheese), and they had to select one of the two words. The idea behind this semantic priming task is that a word is recognized faster if it is preceded by a related word, so the reaction times of the participants were measured (Spitzer et al. 1996). This method was used also in a recent LSD study, which found that participants on LSD made more errors in naming objects from the same category (e.g., say hand instead of leg) than objects from different categories. This lexical substitution error indicates that psychedelics enhance the spread of semantic network activation around a target word. These results support the entropic brain hypothesis (Carhart-Harris et al., 2014), which states that psychedelics render brain activity and associated psychological functions less predictable (Family et al. 2016).

Studies like these are not only exciting, but also insightful for both linguistics and therapy. Unfortunately, governments and institutions are not eager to fund research on psychedelics, because they are scheduled drugs and are associated rather with the hippie culture. Hopefully, in time and backed by science, the discourse around psychedelics will change…


  1. Huxley, A. (1954): The Doors of Perception.
  2. Amarel, M. & Cheek, F. (1966): Some effects of LSD-25 on verbal communication. In: Journal of Abnormal Psychology.
  3. Carhart-Harris, R. (2014) : The entropic brain hypothesis: a theory of conscious states informed by neuroimaging research with psychedelic drugs. In: Frontiers in Human Neuroscience 8(20).
  4. Dahlberg, C. (1974): Effects of LSD 25 on Psychotherapeutic Communication. In: Psychopharmacological Bulletin 10(2), 64-65.
  5. Family, N. et al. (2016): Semantic activation in LSD: evidence from picture naming. Language, Cognition and Neuroscience.
  6. Fink, M., Jaffe, J., & Kahn, R.L. (1960): Drug-induced changes in interview patterns: linguistic and neurophysiologic indices. The Dynamics of Psychiatric Drug Therapy.
  7. Jaffe, J., Dahlberg, C., Luria, J., & Chorosh, J. (1973): Effects of LSD-25 and dextroamphetanune on speech rhythms in psychotherapy dialogues. In: Biological Psychiatry 6(1), 93-96.
  8. Jaffe, J., Dahlberg, C., Luria, J., & Chorosh, J. (1972): Speech Rhythms in patient monlogues; the influence of LSD-25 and dextroamphetamine. In: Biological Psychiatry 4(3), 243-246.
  9. Luria, J. (1974): An Investigation Of Interactions Among LSD Dextroamphetamine and Verbal Behavior In Monologues And Dialogues. Diss.Abstr.Intern.B. 34(11).
  10. Natale, M., Dahlberg, C., & Jaffe, J. (1979): The Effects Of LSD-25 And Dextroamphetamine On The Use Of Defensive Language. In: Journal of clinical Psychology 35, 250-254.
  11. Natale, M., Dahlberg, C., & Jaffe, J. (1978): Effect of Psychotomimetics (LSD and Dextroamphetamine) on the Use of Figurative Language During Psychoanalysis. In: Journal of Consulting and Clinical Psychology 46(6), 157-158.
  12. Rossell, S., Shapleske, J., & David, A. (2000): Direct and indirect semantic priming with neutral and emotional words in schizophrenia: Relationship to delusions. Cognitive Neuropsychiatry 5(4), 271–292.

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