The paradoxical psychological effects of lysergic acid diethylamide (LSD)

• Published in: Psychological medicine Vol. 46; no. 7; pp. 1379 - 1390
• Main Authors: Carhart-Harris, R. L., Kaelen, M., Bolstridge, M., Williams, T. M., Williams, L. T., Underwood, R., Feilding, A., Nutt, D. J.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.05.2016
• Subjects: Acids; Acute; Acutely; Adult; Affect - drug effects; Altered states; Cognitive ability; Consciousness; Cross-Over Studies; Delusions; Hallucinogens - administration & dosage; Hallucinogens - pharmacology; Humans; Intoxication; Lability; LSD; Lysergic acid diethylamide; Lysergic Acid Diethylamide - administration & dosage; Lysergic Acid Diethylamide - pharmacology; Lysergide; Mental health; Middle Aged; Mood; Neo Personality Inventory; Openness; Optimism; Original Articles; Personal Satisfaction; Personality tests; Psychological aspects; Psychological well being; Psychosis; Receptor, Serotonin, 5-HT2A - drug effects; Volunteers; Well being; Young Adult; United Kingdom > UK; psychedelics; serotonin; mood; LSD; psychosis
• ISSN: 0033-2917; 1469-8978; 1469-8978
• DOI: 10.1017/S0033291715002901

Lysergic acid diethylamide (LSD) is a potent serotonergic hallucinogen or psychedelic that modulates consciousness in a marked and novel way. This study sought to examine the acute and mid-term psychological effects of LSD in a controlled study. A total of 20 healthy volunteers participated in this within-subjects study. Participants received LSD (75 µg, intravenously) on one occasion and placebo (saline, intravenously) on another, in a balanced order, with at least 2 weeks separating sessions. Acute subjective effects were measured using the Altered States of Consciousness questionnaire and the Psychotomimetic States Inventory (PSI). A measure of optimism (the Revised Life Orientation Test), the Revised NEO Personality Inventory, and the Peter's Delusions Inventory were issued at baseline and 2 weeks after each session. LSD produced robust psychological effects; including heightened mood but also high scores on the PSI, an index of psychosis-like symptoms. Increased optimism and trait openness were observed 2 weeks after LSD (and not placebo) and there were no changes in delusional thinking. The present findings reinforce the view that psychedelics elicit psychosis-like symptoms acutely yet improve psychological wellbeing in the mid to long term. It is proposed that acute alterations in mood are secondary to a more fundamental modulation in the quality of cognition, and that increased cognitive flexibility subsequent to serotonin 2A receptor (5-HT2AR) stimulation promotes emotional lability during intoxication and leaves a residue of 'loosened cognition' in the mid to long term that is conducive to improved psychological wellbeing.