Reward / Drugs of Abuse / Legal Highs (Vince Wilson)

Question 1

What is Dependence Syndrome?

Answer 1

Strong desire or compulsion to take the substance
Difficulties in controlling use (amount, onset, termination)
Physical withdrawal state
Behaviour changes
Tolerance
Progressive neglect of other interests, increasing time spent obtaining and taking substance
Persistence with substance despite detrimental effects e.g. social, cognitive and physical.

Question 2

What are the progressive steps of substance abuse?

Answer 2

Time set aside for getting and using substance
Time increases - drug seeking behaviour and time spent recovering
Social, occupational and recreational activities reduced
Development of tolerance - reduced intensity
Dependence - induced increase in drug use
Withdrawal - continued use despite recognition of problems
Withdrawal induced anhedonia and depression

Question 3

What is the meso-limbic dopamine pathways association with reward pathways of the brain?

Answer 3

Many drugs of abuse increase dopamine release in the nucleus accumbens (NAC)

Opiates, nicotine, amphetamine, cocaine, ethanol, cannabis. ecstasy, barbiturates, caffeine.

Question 4

Which drugs enhance serotonin function?

Answer 4

LSD (lysergic acid diethylamide)

Ecstasy

Question 5

What does the graph of dopamine effect show about the ‘rush’?

Answer 5

The greater and faster dopamine levels peak in the brain, the greater the rush/euphoria
Formulation is a factor.

Question 6

How does formulation effect the euphoria associated with drugs?

Answer 6

IV heroin ‘better’ than methadone by mouth
Inhaling cocaine better than chewing coca leaves
Smoking cigarettes better than chewing tobacco

Question 7

What is Bromocriptine used for?

Answer 7

Stops breast milk production for medical reasons
Problems caused by having inappropriate levels of prolactin
Treating non cancerous tumours in the brain called prolactinomas
Treating Parkinson’s disease (increase dopamine levels)

Question 8

What side effects are associated with Bromocriptine?

Answer 8

Impulse control disorders

Behaviours such as addictive gambling, excessive eating or spending, abnormally high sex drive or an increase in thoughts/feelings
Also Ropirinole

Question 9

How do opiates work?

Answer 9

Heroin, morphine, methadone, codeine
Agonists at G protein coupled opioid receptors that lower neurotransmitter release in brain and periphery.
Analgesia, euphoria
Respiratory depression, dysphoria, sedation

Question 10

What are the acute effects of opioids?

Answer 10

Euphoria, tranquility, miosis, drowsiness, itching, nausea

Question 11

What are the chronic effects of opioids?

Answer 11

Constipation, anhedonia (no enjoyment), depression, insomnia, dependence
Nutritional status tends to be poor, danger of HIV / hepatitis from injecting
Significant tolerance

Question 12

What are the withdrawal symptoms of opioid use?

Answer 12

Craving, restlessness, muscle and bone pain, vomiting, diarrhoea, insomnia
Cold flashes with goosebumps (cold turkey)
Kicking movements (kicking the habit)
Major withdrawal symptoms peak 48-72h after last dose and subside after about a week.
Sudden withdrawal from heavy users in poor health can be fatal (less dangerous than barbiturate or alcohol withdrawal).

Question 13

What is cocaine?

Answer 13

Benzoylmethylecgonine / alkaloid extracted from the coca tree
Leaves chewed in Peru etc

Question 14

How is cocaine taken?

Answer 14

Snorted, (hydrochloride can cause perforation of nasal septum), or smoked with tobacco.

Question 15

What are the effects of cocaine?

Answer 15

Euphoria and excitement, increased capacity for work

Question 16

How does cocaine cause effects?

Answer 16

Increased catecholamine neurotransmitter function by preventing re-uptake
DA most importnat for CNS behaviour

Question 17

What happens in high doses of cocaine?

Answer 17

Overactvity of sympathetic system

Hypertension, tachycardia, hyperpyrexia, dilated pupils, palpitations

Question 18

What is ‘crack’?

Answer 18

Free base that can be smoked

Very rapid dependence

Question 19

Is cocaine addictive?

Answer 19

STRONG Psychological dependence; very little physical tolerance or physical dependence.

Question 20

What is ‘speed’?

Answer 20

Amphetamine 
Phenyethylamine drugs (methamphetamine)

Question 21

What are the effects of amphetamines?

Answer 21

Increased wakefulness, concentration
Performance enhancing (some tolerance)
Euphoria, increased libido, energy, self esteem and confidence, aggression, excessive feelings of power, obsession and paranoia.

Question 22

How do amphetamines work?

Answer 22

Release monoamines from neuronal synaptic DA, NA, 5HT uptake transporters, causing increased synaptic NTs

Question 23

What is amphetamine psychosis?

Answer 23

Chronic or high dose use can induce

Increases cardiovascular tone, raised BP, tachycardia

Question 24

What is the active agent in cannabis?

Answer 24

THC mimics effect of small endogenous lipid messengers (anandamide).

Question 25

How does cannabis work?

Answer 25

Inhibits a wide range of NT release in the brain and periphery via specific Gi protein coupled cannabinoid receptors.

Question 26

What are the effects of taking cannabis?

Answer 26

Mild euphoric effect; dysphoric in high doses, especially in naive users. Context dependent
Very low acute toxicity but some concern re precipitation of psychosis in chronic users
Stimulates appetite through actions on feeding centres in hypothalamus

Question 27

What treatment is known as agonist substitution?

Answer 27

Methadone treatment for opiate abuse
Long-acting synthetic opiate agonist administered orally for sustained period at dose sufficient to prevent opiate withdrawal.

Question 28

What is the benefit of methadone treatment?

Answer 28

Blocks illicit opiate use and decreases opiate craving

Patient stabilises on adequate sustained doses and can hold jobs, avoid crime and violence and reduces exposure to HIV.

Question 29

What are the formulations of nicotine replacement therapy?

Answer 29

Gum patches sprays etc

*Relatively ineffective in patient long term smoking cessation

Question 30

What partial receptor agonists are used to help quit smoking?

Answer 30

Varenicline (Champix) - nicotinic Ach

Question 31

What partial receptor agonists are used to help withdrawal from opioids?

Answer 31

Buprenorphine u opioid

Question 32

What short term antagonist treatments are available in the treatment of substance abuse?

Answer 32

Naltrexone: therapy for opiate addiction, patients must be detoxified and opiate free for several days to prevent precipitating opiate abstinence syndrome.

Mecamylamine: nicotinic acetylcholine receptor antagonist that blocks the rewarding actions of nicotine and cue-induced craving

Question 33

What is Acamprosate’s role in anti-craving treatment?

Answer 33

Use as adjunct in maintaining abstinence in alcohol dependent patients.
Reduces neuronal excitability that occurs during alcohol withdrawal.