Addiction

Question 1

What are the two proposed mechanisms for dependence?

Answer 1

Tolerance (physiological dependence) 
Reward centre (basis of craving)

Question 2

Define tolerance

Answer 2

Reduced responsiveness to a drug caused by previous admission

I.e. the drug is becoming less effective which each use

Question 3

Give examples of drugs which show tolerance

Answer 3

Opoids, benzodiazepines, ethanol, barbiturates

Question 4

What is tolerance an example of?

Answer 4

A homeostatic mechanism

Question 5

What are the two kinds of tolerance? Give examples of each

Answer 5

Dispositional tolerance = less drug reaches active site
E.g. less absorption, faster metabolism, increased excretion

Pharmacodynamic tolerance = drug has less effect at active site
E.g. fewer receptors (e.g. due to downregulation/internalisation), less efficient receptors (e.g. due to reduced signalling downstream)

Question 6

Why does tolerance lead to dependence?

Answer 6

Body adjusts to the drug as by the mechanisms mentioned, such that the drug has a lesser effect
These changes mean that when the drug is stopped, symptoms are experienced which are the opposite of the effects of the drug (withdrawal symptoms)

Question 7

Give examples of the normal effect and withdrawal effect of:
Opioids
Barbiturates
Cocaine

Answer 7

Opioids - constipation normally, WE = diarrhoea
Barbiturates - anticonvulsants, WE = consulsions
Cocaine - elevated mood, WE = depressed mood

Question 8

Describe the anatomy of the reward centre

Answer 8

VTA neurons project to the nucleus accumbens and release dopamine there
Nucleus accumbens linked to prefrontal cortex and release of dopamine –> sense of pleasure/reward

Question 9

What normally activates the reward centre?

Answer 9

Sex, food, drinking

Question 10

How do the following drugs interact with the reward centre:
Heroine 
Amphetamine 
Cocaine
Alcohol?

Answer 10

Heroine - increased dopaminergic neuron firing
Amphetamine - increases dopamine release
Cocaine - inhibits uptake of dopamine
Alcohol - works via inhibitory neurons

Question 11

What is the prison sentence for possession/dealing of class A drugs?

Answer 11

10 years

Question 12

What is the prison sentence for possession/dealing of class B drugs?

Answer 12

5 years

Question 13

What is the prison sentence for possession/dealing of class C drugs?

Answer 13

3 years

Question 14

What is a huge factor making heroine so dangerous?

Answer 14

Associated with criminality, poor mental health and family life

Question 15

What is a huge factor making cocaine so dangerous?

Answer 15

It is so expensive –> financial problems and social fall out

Question 16

What are two stimulants?

Answer 16

Cocaine

Amphetamine

Question 17

What is crack cocaine?

Answer 17

Purified cocaine

You can smoke this

Question 18

What ways can you take cocaine?

Answer 18

Snorting, smoking, injecting

Question 19

How fast acting is cocaine? How long does its effects last?

Answer 19

Fast acting, short acting

Question 20

What are the effects of cocaine?

Answer 20

Euphoria
Increased alertness
Impaired judgement Increased energy 
Increased confidence
Lessens appetite and need for sleep

Question 21

What are the negative effects of cocaine?

Answer 21

Damages nose and airway (vasoconstrictor) 
Cardiac arrhythmias and MI
Convulsions and respiratory failure 
HTN and CVA 
Toxic confusion 
Paranoid psychosis

Question 22

What are the withdrawal effects of cocaine?

Answer 22

Opposites of effects
Hypersomnia
Hyperphagia 
Depressed mood
Irritability and agitation 
Craving

Question 23

How is amphetamine generally taken?

Answer 23

Amphetamine sulphate

Sniffed, snorted or injected

Question 24

What are the effects of amphetamine?

Answer 24

Similar to cocaine but longer lasting

Question 25

Give examples of opiates

Answer 25

``` Opium Morphine Diamorphine (heroine) Methadone Codeine and dihydrocodeine ```

Question 26

How do opiates work?

Answer 26

Act on opiate receptor to reduce pain and stimulate reward centre

Question 27

What are the different ways of taking heroine?

Answer 27

Sniffing, smoking, injecting | People tend to resort to injecting when their tolerance increases

Question 28

What are the effects of heroine?

Answer 28

``` Analgesia Drowsiness, sleep Euphoria Respiratory depression Cough reflex suppression Sensitisation of labyrinth (--> N/V) Bradycardia/hypotension Lowering body temp Pupillary constriction Constipation ```

Question 29

What is respiratory arrest with pulse almost pathognmonic of?

Answer 29

Opiate OD

Question 30

What tends to happen on first use of opiates?

Answer 30

NV and headache

Question 31

What are short term consequences of opiate use?

Answer 31

Phlebitis Anorexia Constipation

Question 32

What are long term consequences of opiate use?

Answer 32

Tolerance Withdrawal Social and health problems

Question 33

What are the symptoms of opiate withdrawal?

Answer 33

``` Craving Insomnia Muscle pain and cramps Increased salivation, nasal and lacrimal secretions Dilated pupils Yawning Piloerection ```

Question 34

Why is methadone good to use in heroine addicts?

Answer 34

Decriminalises drug use Stops IV use and reduces problems assoc. with that Normalises life

Question 35

What is the biggest problem with ecstasy/MDMA?

Answer 35

Over half of ecstasy tablets don't contain any MDMA

Question 36

What are the effects of MDMA?

Answer 36

Euphoria Increased sociability Inability to distinguish between real and fake

Question 37

What are the side effects of ecstasy use?

Answer 37

Nausea Dry mouth Increased BP and temp Dehydration in clubs

Question 38

What can larger doses of MDMA cause?

Answer 38

Anxiety, panic, psychosis

Question 39

What can long term use of MDMA cause?

Answer 39

Chronic anxiety and depression and insomnia

Question 40

What are the two active compounds in cannabis and what do they do?

Answer 40

THC - psychoactive substance | CBD - antipsychotic and anti-anxiety

Question 41

What are the effects of cannabis?

Answer 41

``` Relaxing or stimulating Increased sociability increased hilarity Synaesthesia Changes in time perception Increased appetite ```

Question 42

In higher doses what can cannabis cause?

Answer 42

Anxiety and panic, persecutory ideation, hallucinations

Question 43

What are anabolic steroids illegally used for?

Answer 43

Building muscle and reducing fat | Especially builds pectorialis, trapezius, biceps and deltoids

Question 44

What are the side effects of steroid use?

Answer 44

``` Acne, hair thinning, stretch marks Feminisation/virulization HTN, hypercholesterolaemia Growth deficits (as premature fusion of epiphyseal plates Liver tumours, cholestatic jaundice Irritability/anger (roid rage) Mania/hypomania Suicidal ideation/depression on withdrawal ```