Lecture 19 - Psychedelics and Cognition Flashcards
Classic psychedelics
Lysergic acid diethylamide (LSD),.. lab-made… little paper
N,N-Dimethyltryptamine (DMT),… plant (tea)
Psilocybin, … magic mushrooms
Mescaline… cactus
● Psychedelics = From Greek: “Mind-manifesting”
● Agonist action at 5-HT2A serotonin receptors
● Common subjective effects
○ Profoundly altered consciousness
● Different duration
Very Very Brief History
Beginnings of human history - Indigenous practices all over the
world
1950’s-1960’s - Early research shows therapeutic potential for
psychological issues
Early 1960s - LSD as a recreational drug, hippies, stigma
1968 - Psychedelics outlawed in USA & Canada
1990’s - Research slooooowly picks back up
2022 - Health Canada Special Access Program
Why talk about
psychedelics?
Because they’re around, more and more, and they don’t seem like they’re about to go away.
● Data shows increases in psychedelic use
● Increased availability
● Research on different aspects of psychedelics and psychedelic use
● Public and private (and underground) psychedelic therapy clinics
Both recreational and therapeutic uses
Have been legalized in a few US states in the recent years
Psychotherapeutics
Studies support the therapeutic use of psychedelics in
the treatment of a variety of conditions.
● Major depressive disorder
● Obsessive compulsive disorder
● Substance abuse
● Post-traumatic stress disorder & complex
trauma
● Anxiety disorders…
Shown to help dispel internalized shame and
interpersonal trauma for marginalized populations.
Generally safe treatment!
No toxic dose found so far
-But doesn’t mean no risks
Subjective Effects
Ego dissolution: sense of no longer existing as a distinct entity
Mystical experiences: experiences of oneness and transcendence
Heightened emotions: euphoria, grief, terror
Sensory alterations: hallucinations, synesthesia, enhanced sensations
Impacts on Cognition
Creativity: Mixed results, anecdotal
evidence for increased creativity
Memory: Impaired working memory at
high doses, potentially impaired
recall
Planning: Impaired
Speed: Longer delays for executive
control and recall
Empathy: Empathy may be increased
What do
classic
psychedelics
do to your
brain?
- Accelerated Neurogenesis
● Consumption of psychedelic substances might
accelerate neuronal growth for a time
-Lasts a few days or weeks after taking the substance
○ Prefrontal cortex
○ Mesolimbic pathway
–Hippocampus
● Decreased neuronal density in several
psychopathologies
Prefrontal cortex and hippocampus have lower number of neurons for people with depression, anxiety…
-maybe taking psychedelics restores neuron density?
● Speed up the rate of psychological and neurological
change
-Create new pathways, consolidate your gains in therapy = speed up change - Decrease in functional connectivity
… does not persist beyond trip
Brain doesn’t coordinate very well anymore
Disruptions:
Decreased functional connectivity between
certain areas of the brain that form stable
networks under normal consciousness
‘Disintegration’ of the Default Mode
Network
● Associated with self-referential
cognition such as autobiographical
memory, and self-awareness
Increases:
Increased overall functional connectivity
has been found in some studies, in some
networks
Increased functional connectivity between
visual processing areas and other parts of
the brain - Entropy
● Increased entropy (randomness) in brain activity
-Parts firing whenever they want, not really coordinating
● Decreased activity of medial prefrontal cortex and posterior cingulate
cortex AND decreased connectivity
● Entropic brain theory: psychedelic states of consciousness are more ‘raw’
in that they represent an unconstrained, base level of consciousness on
top of which normal consciousness is layered
● Some hallucinations may result from random brain activity and reflect
the anatomical organization of our visual system - Decreased top-down processing:
Decreased contribution of higher-level
information (beliefs, priors, patterns) to
consciousness
-Priors = prior knowledge (top-down)
–Lose some of those priors on psychedelics
5 Increased bottom-up processing:
-Increased processing of lower-level
information (sensory, perceptual,
emotional…)
The REBUS Model
● Relaxed Beliefs Under pSychedelics
● Integrates the entropic brain theory, takes it to
another level of analysis
● Decreased top-down processing → loosened priors
about self, the world
● Liberation of bottom-up flow of information →
Updated priors based on incoming information
● These mechanisms can reasonably explain all
subjective effects of classic psychedelics
Role of Priors in Normal
Consciousness:
● Make predictions
○ Engage in goal-directed behaviour
○ Survive
● Filtering Role
○ Process only relevant or valuable information - streamline cognition
○ Maintain continuity of experience over time
Relaxed priors unlock entirely different ways of experiencing the
world
So, so many priors…
Self -
I am a distinct person from you.
I have a body with two legs, two arms, a head…
Others -
People always want something from me.
Emotions -
Anger is a bad emotion - I must not feel anger.
The safest response to sadness is denial.
Time -
Time moves at a steady pace.
The cause always comes before the effect.
Behavioural sequences -
In order to put on a pair of pants, I must put my right
foot in the right hole and my left foot in the left hole.
Laws of physics -
Inanimate objects don’t breathe.
People and objects have a constant size and shape.
Attention -
The shape of this object is more relevant than the
specks of dust on its surface.
Ridity
Overattachment to priors
Priors that resist updating based on current contextual
information can trap us in patterns of thought, emotion and
behaviour that are no longer helpful.
● Phobias - Dogs are extremely dangerous
● Depression - I am a worthless person
● Borderline Personality - I must do everything in my power so
that I am not abandoned
● Narcissistic personality - Everyone around me is incompetent
Inflexible patterns are at the core of many forms of psychological
suffering.
Psychological Flexibility
Psychological flexibility = ability to fluidly select strategies and
responses according to the current context.
By loosening the grip that priors have on cognition and
perception, psychedelics may promote psychological
flexibility.
Psychological flexibility is associated with well-being.
Psychedelic use is associated with increased psychological
flexibility
Psychological
flexibility is at the
core of ALL
psychotherapies
Therapeutic Psychedelic Experiences
Integration:
Intentional engagement after
the psychedelic experience,
transposing the experience to
‘real life’
-Integration time is very important, longer than time on psyched.
Focus:
Internal vs external stimuli,
attention brought to
therapeutically relevant
materials
Intention:
Specific, clear intention
facilitates therapeutic
experiences
Setting:
Physical space, people, music,
physical comfort
Set:
State of mind, openness,
readiness
Summary
● Classic Psychedelics: LSD, DMT, Psilocybin mushrooms, mescal.
● Early treatment success but banned (war on drugs)
● Subjective effects:
○ Ego dissolution
○ Mystical experiences
○ Heightened emotions
○ Sensory alterations
● Cognition: creativity 😅, memory ⬇, planning ⬇, speed ⬇, empathy ⬆
● Disrupts default mode network → more raw consciousn., c.f. entropic brain theory
● Clinical:
○ Reduces top-down (rigidity, inflexible patterns)
○ Increases bottom-up (empathy, emotions, sensory)
