Summary

This document is a study guide or presentation on psychedelics, specifically LSD. It covers topics such as definitional issues, history, effects, and the biology of hallucinations related to LSD. It discusses the drug's mechanisms of action and effects on the brain. The document also describes different forms of LSD, such as blotters, powder pellets, and gelatin chips.

Full Transcript

PSYCHEDELICS 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 History Naturally oc...

PSYCHEDELICS 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 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) History Cont’d Late 60s and 70s “discovered” as agents to: – Enhance and expand reality, 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 Hallucinations and Other Sensory Visual Distortions Colour, Contrast, Size Changes Auditory Sounds amplified, but not always clearer Smell More acute, but recognition can be impaired Taste Tastes linger, but recognition can be impaired Touch Tactile sensations more intense Synesthesia 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 – Stage 2: meaningful images of people, animals, places Images can change rapidly; and changes will typically have a pattern Nature of Hallucinations Cont’d Colours shift from blues to reds as drugs effects intensify At high doses, people will get swept up into hallucination BIOLOGY OF HALLUCINATIONS Brain areas believed to be involved in hallucinations are – Thalamus Traffic officer for incoming sensory information Activity modulated by glutamate, GABA, dopamine, and serotonin – Cerebral Cortex Primary and secondary cortex – Default Mode Network Connected brain areas in the frontal and parietal lobes that are active when someone is not focused on outside world BIOLOGY OF HALLUCINATIONS Psychedelics alter neurotransmitter activity in thalamus – Changes in the overall balance between excitatory and inhibitory – Disrupted activity in thalamus leads to poor filtering of sensory information Disrupted activity in thalamus leads to disruption in the connections to the cortical areas – Release of control on the Default Mode Network such that it becomes more active and more top- down processing of incoming sensory information BIOLOGY OF HALLUCINATIONS Over and above effects on neurotransmitter activity in the thalamus, psychedelics alter neurotransmitter activity in prefrontal cortex, limbic system, 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 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 LSD Effects Second Phase –Characterized by 4 different effects 4. Strange and exaggerated appearances of objects or experiences LSD Effects Third Phase –Begins within approx 3 – 5 hours –Characterized by: 1. Great swings in emotions or panic LSD Effects Third Phase –Characterized by: 2. Feeling of timelessness LSD Effects Third Phase –Characterized by: 3. Feeling of ego disintegration, or separation of one’s mind from one’s body LSD Effects Other effects include: (1) Euphoria (2) Development of Insight (3) Impaired Cognition (e.g., confusion) (4) Bizarre thoughts or feelings (e.g., can fly) LSD Toxicity Low level of “physiological toxicity” Harmful consequences of sensory/psychological alterations Other consequences include: (1) Flashbacks aka Hallucination Persisting Perception Disorder (HPPD) Flashbacks Reexperiencing of LSD trip or spontaneous memories of a trip complete with images, sensations, and emotions Typically only last a few seconds Tend to occur within first few days after a trip, then decrease in frequency, eventually disappear (caveat: some reports of years after drug taken) Triggered by darkness, stress, fatigue, acute alcohol or cannabis intoxication, idiosyncratic factors Unknown mechanism HPPD Re-experiencing of the perceptual disturbances causing significant distress in social, occupational and other areas of functioning Occurs primarily after LSD use, but not exclusively Can last for weeks, months, or years No strong correlation between occurrence and frequency of hallucinogen use Prevalence is approx. 4.2% Possible genetic factors re: risk of developing LSD Tolerance Tolerance to both psychological and physical effects develops Tolerance due to down regulation of 5-HT2A receptors Disappears within approx. a week Cross tolerance with other psychedelics LSD Dependence No physiological dependence Some psychological dependence in some people

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