16 - Drug Dependence and Abuse

Question 1

Drug dependence

Answer 1

State where drug taking becomes compulsive taking precedence over other needs

Question 2

Drug abuse

Answer 2

Use of illicit substances (or illicit use of legal substances) characterised by recurrent and clinically significant adverse consequences

Question 3

Brain areas involved in reqard and salience

Answer 3

Nucleus accumbens, ventral pallidum

Question 4

Main brain reward centre

Answer 4

Nucleus accumbens

Question 5

Brain areas involved in memory and learning

Answer 5

Hippocampus, amygdala

Question 6

Brain areas involved in motivational drive

Answer 6

Orbitofrontal cortex, subcallosal cortex

Question 7

Brain areas involved in inhibitory control

Answer 7

Prefrontal cortex, anterior cingulate gyrus

Question 8

Broad feature of addictive drugs

Answer 8

Increase dopamine in the nucleus accumbens

Question 9

Key neurotransmitters modulating dopaminergic transmission 
1
2
3
4
5
6

Answer 9

1) Acetocholine
2) Serotonin
3) Noradrenaline
4) GABA
5) Glutamate
6) Opioids

Question 10

Effects of amphetamines

Answer 10

Displaces noradrenaline from sympathetic nerves.
Also affect transmission involving dopamine and serotonin.
Appetite suppressant.

Question 11

Tolerance effect of amphetamines

Answer 11

Dose increases for the same effect with long-term use

Question 12

Dependence effect of amphetamines
1 a
2 b

Answer 12

– Psychological not as marked as cocaine
• Particularly depressives, lonely people
– Physical withdrawal
• Lethargy, sleep, desire for food, depression

Question 13

Overdose effects of amphetamines 
1
2
3
4

Answer 13

– Anxiety, nervous & physical tension
– Tremors, confusion, dizziness, time passes quickly
– Hyperthermia, tachycardia, increased blood pressure, vascular collapse - death
– Amphetamine psychosis – hallucinations

Question 14

Effects of caffeine

Answer 14

1) Increases alertness, well-being, no euphoria.

2) Stimulates mental activity

Question 15

Mental effects of caffeine
1
2
3

Answer 15

– Postpone boredom, fatigue, inattentiveness
– Enhanced intellectual / motor performance
• If reduced by fatigue / boredom
– High doses- anxiety, tension & tremors

Question 16

Drug class of caffeine

Answer 16

Methyxanthine.

Adenosine antagonist, phosphodiesterase inhibitor.

Question 17

Action of LSD

Answer 17

CNS agonist at 5-HT2 receptors.

Inhibition of 5-HT neurones in Raphe (autoreceptors)

Question 18

Tolerance of LSD

Answer 18

Rapid, receptor-mediated

Question 19

Brain mechanism for hallucinatory drugs

Answer 19

Serotonin effects in the Raphe nuclei

Question 20

Long-term effects of MDMA

Answer 20

– Psychological dependence
– Increase heart rate, blood pressure
– Disrupted thermoregulation (chills - sweating)
– Potential degeneration of 5-HT & DA neurons
• Affects mood, memory, sleep & appetite

Question 21

Cannabinoid receptors
1
2
3

Answer 21

– CB1-central, CB2-peripheral
– G-protein coupled receptors,
– Inhibition of adenylate cyclase
• Inhibition of signal transmission in the brain

Question 22

Endogenous cannabinoid

Answer 22

Anandamide (physiological role unknown)

Question 23

Synthetic cannabinoid being developed

Answer 23

Nabilone (anti-emetic, peripherally-acting)

Question 24

Ethanol effect
1
2
3

Answer 24

1) Inhibits Ca2+ channel opening
2) Enhances GABA action (through GABA-A receptors)
3) Inhibits glutamate receptors (NMDA channels)

Question 25

Alcohol dependence
1
2
3

Answer 25

– Well defined abstinence syndrome
• Behavioural signs
– Anxiety, Insomnia, Nausea, Anorexia, Delusions, Hallucinations

• Neurological signs
– Tremor, Hyperactive reflexes, Agitation, Delirium, Convulsions, Status epilepticus

• Other physical signs
– Vomiting, Postural hypotension, Sweating, Hyperpyrexia