substance abuse & addiction

Question 1

What are reasons people take recreational drugs?

Answer 1

Reduce anxiety, get high, rebel, boredom, escapism, why not, feel better, like it, stay awake, sleep, curious, fit in, everyone does

Question 2

What is positive and negative reinforcement in terms of drug use?

Answer 2

• Positive reinforcement is to gain a positive state (eg get high, stay awake, escape).
• Negative reinforcement is to overcome adverse state - eg reduce anxiety, sleep, feel better.

Question 3

Why is it important to know why they take drugs?

Answer 3

it informs treatment

Question 4

What is harmful substance use according to ICD-10?

Answer 4

Actual damage should have been caused to mental or physical health of user in absence of diagnosis of dependence syndrome.

Question 5

What is hazardous use?

Answer 5

Likely to cause harm if continues at this level

Question 6

Why do people become dependent on a drug?

Answer 6

neuroadaptations

Question 7

What is needed for diagnosis of dependence syndrome according to ICD-10 diagnostic criteria?

Answer 7

1. strong desire or sense of compulsion to take substance 2. difficulties controlling substance taking behaviour (onset, termination, level)
2. physiological withdrawal state when substance use has stopped/reduced
3. evidence of tolerance (need to take more for same effect)
4. progressive neglect of alternative interests
5. persisting with substance use despite clear evidence of overtly harmful consequences .

Need 3 of these in past months

Question 8

What is addiction?

Answer 8

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

Question 9

What is dependence?

Answer 9

Physical adaptation to substance. Tolerance/withdrawal. Can be dependent but not addicted

Question 10

What are behavioural addictions?

Answer 10

Gambling disorder, internet gaming disorder.

Similarities in aetiology, neurobiology & treatment approaches with substance dependence.

Question 11

What does rate of brain entry of a drug affect?

Answer 11

Faster brain entry causes more rush and more addiction (increases addictive potential)

Question 12

What factors affect addiction?

Answer 12

Genes, family history (more vulnerable to misuse), social/environmental factors, drug factors (faster entry)

Question 13

What is tolerance?

Answer 13

Need to increase dose to get same effect or suffer withdrawal

Question 14

What happens during acute alcohol exposure?

Answer 14

Alcohol blocks excitatory system NMDA receptor (impaired memory, blackouts) and boosts inhibitory system (anxiolysis, sedation) at GABA-A receptor

Question 15

What happens during chronic alcohol exposure?

Answer 15

Neuroadaptations so that GABA and glutamate remain in balance in presence of alcohol.
-Body adapts to reduce sensitivity of GABA (reduces function of inhibitory system) by switch in subunits of GABA-A receptor making it less sensitive to alcohol, and up-regulation of excitatory system

Question 16

What happens during the alcohol withdrawal state? What do we give and why?

Answer 16

Inhibitory system is downregulated, excitatory system is upregulated.

• Withdrawal symptoms because more NMDA receptor, increase in calcium ion entry in cell which is toxic, leading to hyperexcitability (seizures) and cell death (atrophy).
• We give benzodiazepines to boost GABA function and combat excitatory system

Question 17

What is acamprosate?

Answer 17

Drug to help people remain abstinent by reducing NMDA function - reducing glutamate levels in brain.

Question 18

What is the dopaminergic system and what do rewards cause?

Answer 18

• Reward-motivation system.
• Natural rewards increase dopamine in ventral striatum. Going towards dependence, dopamine system becomes more about needing drug.
• Key modulators in opioid system (endorphin modulators) and GABA-B, cannabinoids, glutamate targets for treatment

Question 19

What is addiction thought of as?

Answer 19

Reward deficient state so take drug to increase reward

Question 20

What do drugs do to dopamine?

Answer 20

Amphetamines and cocaine block reuptake of dopamine and enhance release of dopamine.
Other drugs like alcohol and opiates increase dopamine neurone firing in VTA

Question 21

What is relationship between D2 receptor availability and liking a stimulant drug?

Answer 21

• Those with more D2 receptor availability did not really like stimulant drugs.
• Less D2 receptor availability liked stimulant drugs (may be reward deficient - less baseline dopamine levels)

Question 22

What can be seen in fMRI during anticipation of winning?

Answer 22

Ventral striatum lights up (dopamine)

Question 23

Difference in reward system between controls, abstinent and relapse?

Answer 23

Blunted activation of reward system in those with relapse, a bit better in abstinent, a lot better in controls

Question 24

Do all addicts have blunted reward system?

Answer 24

no

Question 25

Where is negative reinforcement or affect (eg anxiety) controlled in the brain?

Answer 25

amygdala

Question 26

When does dysregulation of amygdala happen?

Answer 26

In anxiety disorders and fear.

Stress system increased (in many including kappa opioid - dynorphin), noradrenaline (arousal), CRF (stress).

Question 27

What does change from voluntary drug use to compulsion cause in brain?

Answer 27

Transition from pre-frontal to striatal control over drug taking.
Ventral (emotional) to dorsal (habit) striatum. Becomes dysregulated. Role of memory (hippocampus) in craving

Question 28

What drug used to treat alcohol withdrawal?

Answer 28

benzodiazepines

Question 29

What drug to support abstinence from alcohol?

Answer 29

acamprosate

Question 30

Which drug to block heroin use in opioid addicts?

Answer 30

Naltrexone (opioid antagonist) to block heroin