psychedelics Flashcards
Definitional Issues
Heterogenous group of compounds which:
– Can induce hallucinations
– Separate individuals from reality
– Can induce psychotic-like behavior
No one single term comprehensively classifies
these drugs** because they all can induce hallucinogens and psychodic behaviour (psychotic behvaiour is different from these than meth)
- so they can do more than hallu, and not psychotomimetic
- psychedelic ===> sensory distortion ** why theyre called this
History
- Naturally occurring agents used for thousands
of years – as most derived from plants**
– Ascribed magical/spirtual properties (e.g., Aztecs
and psilocybin, Native Americans and mescaline) –> use in rituals
mescaline –> used by native american church in rituals in healing practices
harmine —> bark of tropical vine in south american
- made into a beverage
DMT –> insect amphibian, plants
–> can be chmically synthesized into a crystalin substabce
- foudn in ayowasca
myristine/elmycin –> found in nutmeg
salvinorum A (salvia) –> come from a mint plant indigenous from awahoo region in mexico
ibotinic acid –> psychoactive ingredient in toadstool mushroom
synthetic:
- albert hoffman made –> LSD
ketamine
PCP
both above are dissociative anaesthetic
- use was discontinued but K was used by vets
History Cont’d
*
Late 60s and 70s “discovered” as agents to:
Enhance and expand reality (of cosmos) , promote personal
awareness, stimulate understanding of spirtual world
During the next five hours, I was whirled
through an experience which could be
described in many elegant metaphors but
which was above all and without question
the deepest religious experience of my life
History Cont’d
* Late 60s and 70s “discovered” as agents to:
– Enhance and expand reality, promote personal
awareness, stimulate understanding of spiritual
world
* Present times:
– Primarily used recreationally
– Used in lower doses
- explored as drugs to be used in therapy, and to treat pain
- doses people are taking are much lower than 60/70s
Hallucinations and Other Sensory
Distortions
Visual
- Colour, Contrast, Size Changes (brighter, more saturated, more contrast (movement popping out in front of you) , smaller or larger than they actually are) , change in shape in front of you , move around (heavy objects move less than smaller objects)
Auditory
- Sounds amplified, but not always clearer ( speech garbled)
Smell
- More acute, but recognition can be impaired
Taste
- Tastes linger, but recognition can be impaired
Touch
- Tactile sensations more intense but its distorted (lost in moving their hands across carpet)
- Synesthesia –> fusing of senses , colours will have sound
Nature of Hallucinations
Hallucinations will occur in stages:
– Stage 1: visual images (e.g., spirals, grids,
geometric patterns) recognized as not being real; first seen with eyes closed than projected on surfaces when eyes opened
–> these images become meaningful (stage 2)
– Stage 2: meaningful images of people, animals, places
* Images can change rapidly; and changes will typically have a pattern (ex see spirals, become tunnel, then tunnel will move)
–> common image seen is eyes staring back at them ***
Nature of Hallucinations Cont’d
* Colours shift from blues/purple to reds/orange as drugs effects intensify
* At high doses, people will get swept up into hallucination –> start to interact with what they are seeing
BIOLOGY OF HALLUCINATIONS
* Brain areas believed to be involved in hallucinations are
Thalamus
–> Traffic officer for incoming sensory information–> filters info as well
–> Activity modulated by glutamate, GABA, dopamine, and
serotonin –> most projections from thalamus are EPSP
Cerebral Cortex
* Primary and secondary cortex involved in eperiencing emtions
–> sensory cortex invoved in recognition of sensroy info
Default Mode Network
–> Connected brain areas in the frontal and parietal lobes
that are active when someone is not focused on outside
world (internally focused,) plays a role in hallucination
BIOLOGY OF HALLUCINATIONS
Psychedelics alter neurotransmitter activity in
thalamus
– Changes in the overall balance between excitatory
and inhibitory synapses (activity gets disrupted, not decreased or increased)
– Disrupted activity in thalamus leads to poor filtering
of sensory information (more sensory info ascending than typical)
- Disrupted activity in thalamus in turn leads to
disruption in the connections to the cortical
areas –> being a Release of control on the Default Mode Network such that it becomes more active causing more top- down processing of incoming sensory information
–> exepctations are what you will see (what you are told it is ) percepts based on memories and expectations play more of a role than actual features***8
BIOLOGY OF HALLUCINATIONS
* Over and above effects on neurotransmitter
activity in the thalamus, psychedelics alter
neurotransmitter activity in prefrontal cortex,
limbic system, brain stem (locus cerileus –> they are enhancing response of locus cerilius to novel information objects capture our focus more) , and temporal parietal cortex.
BIOLOGY OF HALLUCINATIONS
* Imaging studies have shown that
There is increased/overactivity from normal states in
primary and secondary cortex
Auditory hallucinations associated with disrupted
activity in middle and superior temporal lobes
Visual hallucinations associated with disrupted
activity in occipital lobe
Tactile hallucinations – disrupted activity in primary
somatosensory cortex and posterior parietal cortex
most of psych affect serotonin type 2a receptors
LSD
* General Description:
– First use in therapy
– In 60s, recreational use began
– Very potent drug
* Effective dose can be only 10 micrograms, with only one-
hundreth of a percent being absorbed into brain
LSD
ADME
* Odorless, tasteless, no colour
* Usually consumed orally as “hits”
* Forms include:
Powder Pellets
Gelatin Chips
Blotters
LSD
ADME Cont’d
* Rapidly absorbed into bloodstream, an
distributed (most ends up in liver)
* Extensively metabolized (excreted in feces)
* Effects can last up to 12 hours
– peak effects: 90 min to 5 hours
LSD
Mechanism of Action
(1) Agonist of serotonin: activates 5-HT2A
receptors
(1) Suppresses activity/output of locus coeruleus (LC)
(2) Enhances response of the LC to novelty
LSD
Mechanism of Action
(2) Affects activity in the medial prefrontal cortex
via glutaminergic neurons
(3) Inhibits firing and release of serotonin by
raphe nuclei, which may be responsbile for LC
suppression
LSD
Effects
* First Phase
– Begins within 30 min
– Minor physiological effects
– Sensation of release of inner tension
LSD
Effects
* Second Phase
– Occurs within 30 min and 2 hours
– Characterized by 4 different effects
1. Images seen with the eyes closed
LSD
Effects
* Second Phase
– Characterized by 4 different effects
2. Synthesia
LSD
Effects
* Second Phase
–Characterized by 4 different effects
3. Perception of a multilevel reality
