Their findings have important implications for psychiatric disorders, which are often characterized by distortions in personal relevance. In doing so, they also clearly identified how LSD acts on the brain to make people feel the way it does.
Scientists had patients listen to a series of songs and had them rate the level of personal meaning it instilled in them. Under the effects of LSD, stimuli that seemed previously meaningless all of a sudden had immense personal relevance. People under the effects of this powerful, long-lasting psychedelic drug often attribute great significance to events, objects or music around them with seemingly life-transcending influence. Neuroscientists previously thought that LSD acts mainly on dopamine receptors in the brain to make people trip, but this latest research has flipped that idea almost completely on its head.
When the researchers gave their subjects a drug called ketanserin in addition to LSD, the songs they played for them stopped having the life-changing meaning they had while they were only on LSD. Ketanserin, which is mainly used as an antihypertensive, is known to act very specifically on a type of serotonin receptor called 5-HT2. The fact that ketanserin blocked these LSD effects inevitably leads to the conclusion that LSD must act on this serotonin receptor. Their experiment also points to the interesting and unexpected conclusion that the 5-HT2 receptor must have a pivotal role in the brain’s attribution of personal relevance.
“Excessive stimulation of 5-HT2A receptors seems to underlay the experience of loosening of self/ego boundaries, disrupted self-referential processing and thus the related impairment of making meaning and attributing personal relevance to percepts and experiences seen in various psychiatric disorders,” said Katrin Preller from Zürich University Hospital for Psychiatry, lead author on the paper. “Therefore, it is important to consider this receptor subtype as potential target for the treatment of psychiatric illnesses characterized by alterations in personal relevance attribution.”
These findings may help neuropsychopharmacologists design a drug that could help people overcome phobias, low self-worth, depression or PTSD.
Many psychiatric conditions involve the association of a powerful negative meaning with aspects of life or the self. If a drug could somehow block these meanings, it could help “teach” the brain to have a healthier meaning attached to this aspect of life or memory.
Conversely, this new finding could also mean that psychiatrists may one day use LSD as a tool to strategically implant a positive meaning to something in a patient’s life. Instead of a lengthy or indefinite course of traditional psychiatric drugs, one therapy-assisted acid trip could be all someone needs to feel like themselves again, with a rejuvenated outlook on the world.
But wait, what about this mysterious ketanserin? Did scientists discover an anti-LSD?
Subjects in the study claimed it inhibited almost all of the acid trip. Hospitals and emergency clinics could switch to ketanserin as an alternative to benzodiazepines when patients are admitted on acid.
This study comes at a time of increased medical interest in psychedelics, which may one day lead to their full acceptance and legalization.