Substance use and addiction

Question 1

What are the three main reasons people may choose to take drugs/alcohol?

Answer 1

Feel high/Elation/escapism/like it (positive reinforcement),
Sleep/Stress Manage/Withdrawal (negative reinforcement), Society pressure

Question 2

Course of drug use

Answer 2

like -> want -> need
starts with experimental use which becomes increasingly regular use then eventually spirals into dependence.

Question 3

What are the diagnostic criteria for dependence syndrome?
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Answer 3

ICD-10:
1. Compulsion to take drug,
2. Control difficulties, onset, termination and levels of use
3. Withdrawal state, user takes drug to treat this
4. Tolerance, need more to get the same effect
5. Neglect to enjoy activities,
6. Persistent use despite harm

Question 4

What is addiction?

Answer 4

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

Question 5

What is dependence?

Answer 5

Physical adaptation to a substance which cause cause tolerance/ withdrawal.

Question 6

What is the difference between addiction and dependence?

Answer 6

Addiction - compulsive use despite harmful consequences // Dependence - biological tolerance to substance

Question 7

What are some behavioural addictions?

Answer 7

Gambling disorder, internet gaming disorder

Question 8

What is hazardous use?

Answer 8

Drug use is likely to cause harm if it is continued at this level

Question 9

What is harmful use of drugs (with examples)?

Answer 9

Actual damage to physical or mental health of user or those around them.
E.g. smoking with lung disease or getting drunk and fighting

Question 10

What are the three stages of abnormal drug and alcohol use?

Answer 10

Hazardous Use, Harmful Use, Dependence/Addiction

Question 11

Effect of speeding up brain entry

Answer 11

Causes a greater rush an more addiction
e.g. tobacco used to be chewed, but now it is smoked as it gets to the brain faster

Question 12

Influences on drug use and addiction

Answer 12

social/environmental factors
drug factors
personal factors e.g genetic, personality traits

Question 13

What occurs during tolerance?

Answer 13

Compensatory neuroadaptations to maintain normal brain function

Question 14

Describe the natural reward pathway in the brain

Answer 14

Dopamine pathway: dopaminergic neurons that originate in the ventral striatum and project to the substantia nigra

Question 15

What is the mechanism of action of amphetamine at the dopaminergic neurons?

Answer 15

Blocks reuptake of dopamine and releases extracellular dopamine

Question 16

How can you assess the function of the reward pathway?

Answer 16

Functional MRI of ventral striatum and a reward incentive delayed anticipation task (asking to roll two die and if they get 12 then they win something - see ventral striatum activity)

Question 17

How can reward deficiency lead to drug use?

Answer 17

Blunted brain activation of the reward system suggested that those people were more likely to become problematic drug users (often relapse)

Question 18

How is reward system proficiency related to abstinence?

Answer 18

Higher activity in reward system is associated with higher rates of abstinence after drug use

Question 19

What parts of the brain are related to the withdrawal effects?

Answer 19

Amygdala, hippocampus and brainstem

Question 20

Amygdala and drug abuse

Answer 20

Subconscious stress receptor
Activity is dampened by drugs, so in abstinent individuals it becomes overactive

Question 21

Chronic alcohol abuse effect on the brain

Answer 21

Impaired frontal cortex, which causes impaired DM and mood swings.

Question 22

What is the mechanism of action of alcohol, opiates and nicotine at the dopaminergic neurons?

Answer 22

Increased dopaminergic neuron firing rate

Question 23

What is the mechanism of action of cocaine at the dopaminergic neurons?

Answer 23

Block reuptake of dopamine

Question 24

How does the type of reinforcement as addiction develops?

Answer 24

Changes from positive to negative reinforcement

Question 25

What amygdala system is disrupted in withdrawal states and how?

Answer 25

Increased activity in amygdala stress system: increased activity in kappa opioid and noradrenaline (anxiety and arousal)

Question 26

Causes of impulsivity/ compulsivity

Answer 26

Fronto-striatal connections with reduced frontal control of striatal activity and move from ventral (limbic) to dorsal (habit) striatum as dependence develops.

Question 27

How does alcohol alter the balance of the brain’s inhibitory system?

Answer 27

Increases the action of the GABA-A receptor, and hence the inhibitory system
Causes Anxiolysis (relaxed), Sedation

Question 28

How does alcohol alter the balance of the brain’s excitatory system?

Answer 28

Decreases the action of the NMDA glutamate receptor, and hence the excitatory system
Causes Impaired memory (alcoholic blackouts)

Question 29

What is the brain’s compensatory mechanism to alcohol effects?

Answer 29

Neuroadaptations - reduced sensitivity of GABA-A to alcohol // upregulation of excitatory effects

Question 30

How does tolerance of alcohol cause the negative effects of withdrawal?

Answer 30

Loss of balance - higher excitatory system effects than inhibitory functions
NMDA receptor causes increased ca2+ activity leading to Hyperexcitability (seizures) and Cell Atrophy

Question 31

How would you treat alcohol tolerance?

Answer 31

Benzodiazepine - boost GABA-A effects

Question 32

What drug can you use to support abstinence?

Answer 32

Acamprostate (new drug) - blocks NMDA receptor