Drugs of dependence and antidepressants

Question 1

Define drug dependence?

What does it arise from?

Answer 1

State where drug use becomes compulsive, taking precedence over other needs

Arises from drug abuse

Question 2

Define drug abuse?

Answer 2

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

Question 3

Describe the relationship between drug abuse and drug dependence?

Answer 3

Drug dependence arises from drug abuse

Question 4

Describe the common reasons for drug abuse?

Answer 4

Rewarding effects of psychoactive drugs (positive reinforcement)

Habituation or adaptation

Question 5

List some commonly abused drugs?

Answer 5

Question 6

Which circuits are thought to be involved in drug abuse and addiction?

Answer 6

Reward/ salience areas

Memory/learning areas

Motivation/drive areas

Inhibitory control areas

Question 7

What is the key to the positive reinforcement provided by drugs of dependence and abuse?

Answer 7

Increase in dopamine in nucleus accumbens

Question 8

What are the key NTs modulating dopaminergic transmission?

Answer 8

Ach, serotonin, NA

GABA, glutamate

Opioids

Question 9

To which drug class does amphetmaine belong?

Answer 9

CNS stimulant

Question 10

Describe the effect of amphetamine on NTs?

Answer 10

Releases Da, 5-HT and NA in CNS

Question 11

Which variables alter the effects of amphetamine?

Answer 11

Mood

Personality

Environment

Dose

Question 12

Describe the effects of amphetamine?

Answer 12

Mood elevation/euphoria

Increased locomotor activity

Stereotypic behaviour

Improved physical and mental performance (fatigue postponed, confidence, faster performance but less accuracy)

Question 13

Describe the effects of amphetamine overdose?

Answer 13

Anxiety, nervousness and physical tension

Tremors, confusion, dizziness, time passes quickly

Hyperthermia, tachycardia, increased BP, vascular collapse

Amphetamine psychosis - hallucinations

Question 14

Why does amphetamine dependence occur?

When is depedence more likely to occur?

Answer 14

Related to dopaminergic actions in nuclear accumbens

More likely to occur in those starting at a ‘lower basleine’ (i.e. depressives, lonely)

Question 15

Describe the effect of amphetamine on appetite?

Why does this occur?

Answer 15

Appetite suppressant

Thought to be an effect of 5-HT

Question 16

What is MDMA?

Answer 16

MethyleneDioxyMetAmphetamine

‘Ecstasy’

Question 17

Describe the effects of MDMA on NTs?

Answer 17

Release DA and 5-HT

Question 18

Describe the effects of MDMA?

Answer 18

Stimulant and hallucinogenic effects

Question 19

Describe the adverse effects of MDMA?

Answer 19

Psychological dependence

Increased HR and BP

Disrupted thermoregulation (chills, sweating)

Potential degeneration of 5-HT and DA neurons

Question 20

What is LSD?

Which drug class does is belong to?

Answer 20

Lysergic acid diethylamide

Hallucinogen

Question 21

Describe the effects of LSD?

Answer 21

Visual, auditory and tactile hallucinations (sesnory modalitites confused)

Thought processes disturbed but aware

Question 22

Describe the adverse effects of LSD?

Answer 22

Tolerance

Dependence not really an issue (aversive rather than reinforcing)

Question 23

Describe the action of LSD in the body?

Answer 23

Agonist at 5-HT2 receptors

Question 24

Describe the effects of caffeine?

Answer 24

Increases alertness, well-being

Delays onset of sleep

Stimulates mental activity

Question 25

To which drug class does caffeine belong? What is its action?

Answer 25

Methylxanthine Adenosine antagonist, PDE inhibitor

Question 26

Describe the effect of dependence in caffeine?

Answer 26

No strong reinforcing effect in animals Social aspect in humans

Question 27

What is D9-THC?

Answer 27

Active ingredient in cannabis

Question 28

To which drug class does D9-THC belong?

Answer 28

CNS depressant

Question 29

Describe the effects of D9-THC?

Answer 29

Very subjective; influenced by characteristics of drug and individual Sharpened sensory awareness, increased intensity of sounds and sights Relaxation, feeling of well-being

Question 30

Describe the effect of dependence with D9-THC use?

Answer 30

Some evidence of physical and psychological dependence in heavy users

Question 31

Where does D9-THC act in the body? Describe its effect?

Answer 31

Cannabinoid receptors (GPCRs) \> inhibits adenylate cyclase \> inhibition of transmission Two receptor subtypes: CB1 and CB2

Question 32

Describe the effects of ethanol?

Answer 32

Behavioural effects: subjective; increased confidence, euphoria, agression, mood swings Motor effects: loss of coordination, slurred speech Tissue effects: cardiovascular protection, liver damage, neurodegeneration, foetal impairment

Question 33

To which class of drugs does does ethanol belong? Describe its action?

Answer 33

CNS depressant Can inhibit Ca channel opening, enhance GABA action, inhibit glutamate receptors

Question 34

Describe the effects of tolerance and dependence with ethanol use?

Answer 34

Marked tolerance, due to pharmacokinetic effects of enhanced clearance Physical dependence, rather than psychological (well defined abstinence syndrome)

Question 35

Describe the three generations of antidepressant drugs?

Answer 35

1st: tricyclic antidepressants, MAO inhibitors 2nd: SSRIs, SSNRIs 3rd: novel monoaminergic drugs, non-monoaminergic drugs

Question 36

Describe the pharmacological action of tricyclic antidepressants? Describe their selectivity?

Answer 36

Inhinit neuronal uptake of NA and serotonin Anatgonise a-adrenoceptors, MuscR, HA receptors and serotonin receptors Poor selectivity (based around somehow interfering with uptake of NA and serotonin

Question 37

Give three examples of tricyclic antidepressants?

Answer 37

Imipramime Amitryptiline Doxepin

Question 38

Describe the onset of clinical effects of tricyclic antidepressants?

Answer 38

Takes weeks to develop

Question 39

Describe the therapeutic window of tricyclic antidepressants?

Answer 39

Narrow Limited efficacy, side effects become a problem

Question 40

Describe the half lives of tricyclic antidepressants? What impact does this have on dosage?

Answer 40

Longish half-life Gradual accumulation possible, so slowly developing side effects Start dose low to avoid side effects, then increase

Question 41

Describe the pharmacological action of monoamine oxidase inhibitors?

Answer 41

Increase levels of 5-HT, NA and DA

Question 42

Describe the pharmacological effect of SSRIs?

Answer 42

Selective for blocking 5-HT uptake

Question 43

Describe the side effects of SSRIs?

Answer 43

Nausea Insomnia Agitation Weight change Loss of libido