SUBSTANCE USE AND ADDICTIONS

Question 1

List examples of positive reinforcement in causing drug addiction

Answer 1

Escapism
Get high
Like it
Stay awake

Question 2

List examples of negative reinforcement in causing drug addiction

Answer 2

Boredom
Sleep
Reduce anxiety
Feel better

Question 3

What is the ICD-10 classification of harmful substance use?

Answer 3

Actual damage caused to mental/physical health of user in absence of diagnosis of dependence syndrome

Question 4

What is the ICD-10 diagnostic criteria of dependence syndrome?

Answer 4

3 or more in the past 12 months:
- Strong desire/sense of compulsion to take substance
- Difficulty controlling substance taking behaviour in
terms of onset, termination, levels of use
- Physiological withdrawal state when substance use has
stopped/reduced
- Evidence of tolerance (need to take more)
- Progressive neglect of other interests
- Persistent substance use despite clear evidence of
harmful consequences

Question 5

What are the 2 types of harm caused by drug use?

Answer 5

Harm to users

Harm to others

Question 6

What is the definition of addiction?

Answer 6

Compulsive drug use despite harmful consequences, characterised by an inability to stop using; failure to meet work, social or family obligations

Tolerance + withdrawal depending on drug

Question 7

What is the definition of dependence?

Answer 7

Physical adaptation to a substance
- tolerance/withdrawal

Can be dependent and not addicted

Question 8

What are some examples of behavioural addictions?

Answer 8

Gambling disorder

Internet gaming disorder

Question 9

What does a faster effect/entry on the brain from a drug cause?

Answer 9

More “rush” and more addiction

Coca leaves –> Coca paste –> Cocaine –> Crack
Chewing tobacco –> Snuff –> Cigs/vaping

Question 10

How does the brain change from drug use to addiction?

Answer 10

Pre-existing vulnerability e.g. family history, age

Drug exposure causing compensatory neuroadaptations to maintain brain function

Cycles of remission and relapse or sustained recovery

Question 11

Why are younger individuals more likely to be addicted?

Answer 11

High neuroplasticity in younger individuals

Question 12

How does alcohol work?

Answer 12

Enhances benzodiazepine and GABA-A receptor coupling making it more efficient. Increased inhibitory system

Alters the balance between brain’s excitatory (glutamate-NMDA receptor) and inhibitory system

Question 13

What does drinking acutely cause?

Answer 13

Excitatory system blocked (impaired memory)

Inhibitory system boosted (anxiolysis, sedation)

Question 14

What does chronic alcohol exposure cause?

Answer 14

Upregulation of excitatory system (more NMDA receptor)
Reduced function in inhibitory system (tolerance)
- GABA-A receptor switches subunits to be less sensitive
to alcohol

Question 15

What occurs in alcohol withdrawal after chronic drinking?

Answer 15

Neuroadaptations meaning GABA and glutamate systems no longer in balance

Due to more NMDA receptors (upregulation) increase in Ca2+ inside cells which is toxic and causes hyperexcitability (seizures) and cell atrophy

Question 16

How do we treat alcohol withdrawal?

Answer 16

Benzodiazepines e.g. diazepam to boost GABA function and counter increase of NMDA receptors

Question 17

What is acamprosate?

Answer 17

Medication to help people remain abstinent - reduces NMDA function

Potentially neuroprotective

Question 18

What are the models/causes of addiction?

Answer 18

Reward deficiency (+ve reinforcement)
Overcoming adverse state e.g. withdrawal, anxiety (-ve reinforcement)
Impulsivity/compulsivity

Question 19

What is the chemical released in response to reward and where?

Answer 19

Dopamine

Ventral striatum

Question 20

What is the dopamine pathway often referred to as?

Answer 20

Pleasure-reward-motivation system

Question 21

What are some key modulators of the reward system?

Answer 21

Opioid system particularly mu opiod which mediates pleasurable effects
GABA-B
Cannabinoids
Glutamate

Question 22

How do cocaine and amphetamine work?

Answer 22

Cocaine blocks dopamine reuptake

Amphetamine blocks dopamine reuptake and enhances release of dopamine

Question 23

How do alcohol, opiates and nicotine work?

Answer 23

Increase dopamine firing in ventral tegmental area (VTA)

Question 24

What is the relationship between availability of D2 receptors and psychostimulant effects?

Answer 24

Those with high D2 receptor didn’t find stimulant as enjoyable as those with less available D2 receptors

Excess dopamine can cause paranoia and anxiety

Question 25

How can we assess function in the reward pathway?

Answer 25

fMRI

Question 26

Which areas of the brain are associated with binge/intoxication?

Answer 26

Ventral striatum
Dorsal striatum
Globus pallidus
Thalamus

Question 27

Which areas of the brain are associated with withdrawal/-ve effect?

Answer 27

Ventral striatum
Amygdala
Brainstem

Question 28

Which areas of the brain are associated with preoccupation/anticipation craving?

Answer 28

Hippocampus
Orbitofrontal cortex
Medial prefrontal cortex

Question 29

What is the relationship between +ve and -ve reinforcement as addiction/dependence develops?

Answer 29

Overtime, +ve reinforcement intensity goes down and -ve reinforcement keeps going up

A lot of people take the drug to overcome -ve state rather than chasing a high

Question 30

What is the stress system?

Answer 30

Kappa opioid - Dynorphin
Noradrenaline (arousal system)
CRF

Question 31

What is often dysregulated/targeted in neuropharmacological treatment of withdrawal?

Answer 31

Amygdala

Question 32

What occurs in the brain during a change from voluntary drug use to more habitual/compulsive drug use?

Answer 32

Transition from:

• Prefrontal to striatal control over drug taking
• Ventral to dorsal striatum

Role of memory in craving