Psychiatric drugs

Question 1

learning objectives

Answer 1

• To be able to describe the pharmacological actions of key psychoactive drugs used in neuropsychiatry
• To list some key indications for psychoactive drugs in neuropsychiatry (clinical and research)
• To understand some of the potential neuropsychiatric harms of psychoactive drugs

Question 2

psychoactive drugs in neuropsychiatry

Answer 2

• cannabinoids
• stimulants
• dissociative drugs
• therapeutic sedation
• psychedelics

Question 3

what are the cannabinoids

Answer 3

• cannabis
• CBD (cannabidiol)

Question 4

CBD

Answer 4

• cannabidiol
• non psychoactive
• contains 0.3% THC or less

Question 5

THC

Answer 5

• tetrahydrocannabinol
• psychoactive
• contains more than 0.3% THC

Question 6

what is the name of the receptors in the cns that cannabis works on

Answer 6

endocannabinoid receptors

Question 7

where are endocannabinoid receptors found

Answer 7

• spinal cord
• periacequeductal grey in th brain stem

Question 8

what is the periacqueductal grey responsible for

Answer 8

pain modulation

Question 9

what are the responses to THC binding to the cannabinoid receptors

Answer 9

• release of GABA and glutamate in the presynaptic neuron
• release of amantadine and 2-AG in the post synaptic neurons
• activation of CB1 and CB2 receptors in the presynaptic neuron

Question 10

subjective acute effects of thc

Answer 10

• euphoria
• increased appetite
• tiredness
• cognitive slowing
• motor slowing
• anxiety
• paranoia
• psychosis

Question 11

what year did doctors become able to prescribe herbal cannabis

Answer 11

2018

Question 12

sativex

Answer 12

• synthesised thc/ cbd
• oromucosal spray
• multiple sclerosis
• spasticity
• 1:1 ratio

Question 13

research evidence for cannabis use

Answer 13

• back pain
• chronic/ neuropathic pain
• anxiolytic for agitation and anxiety in AD/ BPSD

Question 14

research evidence against cannabis

Answer 14

• cannabis use is a risk factor for developing psychosis (approximately doubles risk in comparison to nautrally occuring risk in the general population - 1%)

Question 15

explainig the anxiolytic effects of cbd

Answer 15

anxiolytic effects may be mediated by placebo expectation

Question 16

stimulants

Answer 16

amphetamines
MDMA

Question 17

effects of amphetamine

Answer 17

wakefullness
euphoria - limbic regions
concentration/ focus
reward - ventral tegemental region

Question 18

uses of amphetamines

Answer 18

ADHD

Question 19

how do amphetamines work

Answer 19

stimulate the release of dopamine in the presynaptic terminal
block the reuptake of dopamine from the synaptic cleft
increases firing in the dopaminergic neurons

Question 20

ADHD stimulant medications

Answer 20

methylphenidate
dexamphetamine
lisdexamphetamine

Question 21

mechanism of stimulants

Answer 21

dopamine and noradrenaline reuptake inhibitor

Question 22

side effects of stimulants

Answer 22

potential for abuse
insomnia
increased heart rate
increased BP
nausea and vomiting
abdominal pain
decreased apepite
decreased weight and growth

Question 23

off licensed uses for stimulants

Answer 23

narcolepsy - excessive daytime sleepiness and catalepsy
alzheimers - apathy
TBI - cognitive function and fatigue
chronic fatigue syndrome - fatigue
depression - apathy

licensed

Question 24

3,4-Methylenedioxymethamphetamine (MDMA)

ectasy or molly

Answer 24

• works on dopamine and serotonin
• dopamine released from the presynaptic cleft and inhibited serotonin reuptake into the presynaptic cleft
• increases firing of the post synaptic serotonergic terminals

Question 25

absolute risk of ecstasy compared to horse riding

Answer 25

higher risk of acute harm from horse riding

Question 26

MDMA for PTSD

Answer 26

* aims to increase engagement in therapy * concerns over abuse * unavoidable unblinding

Question 27

dissociative drugs

Answer 27

nitrous oxide ketamine

Question 28

how does nitrous oxide work (targets)

Answer 28

glutamate - NMDAR/ AMPAR antagonist, decreased glutamate release in the amygdala GABA - GABAA receptor potentiation/ GABAC receptor antagonist, disinhibitory effects in the hippocampus other receptors and channels e.g calcium, serotonin very short term effects

Question 29

ketamine in depressed patients

Answer 29

depressed patients undergoing elective surgery reported antidepressant effects from ketamine and placebo

Question 29

ketamine

Answer 29

anaesthetic and antdepressant effects NMDAR antagonsit inhibits GABA and increases glutatmate

Question 30

psychedelics

Answer 30

psilocybin LSD acid

Question 31

mechanism

Answer 31

potent serotonin 2a receptor agonist association cortices

Question 32

psychedelic effects on networks

Answer 32

desegregation of functional brain networks

Question 33

expectancy and suggestibility in escitalopram vs psilocybin for depression

Answer 33

* participants asked before trail if they are randomised to antidepressant vs psychedelic do they think they will get better * 100% expectancy is full belief they will get better * greater expectation that antidepressant will get them better * suggestibility increases response to psilocybin

Question 34

manipulating the effects of psychodelics

Answer 34

suggestibility contextual factors