Schizophrenia - Treatment 1

Question 1

What are the pharmacological and non-pharmacological treatments for schizophrenia?

Answer 1

pharmacological

• typical antipsychotics = 1st generation
• atypical antipsychotics = 2nd generation

non-pharmacological
- electroconvulsive therapy (severe symptoms/resistance)
= stimulation of the brain and skull by applying an electric shock/current
- cognitive behavioural therapy

Question 2

What are antipsychotics? What do they do? What pathways do they act on?

Answer 2

are D2 antagonists
- block dopamine 2 receptors

all initially show an increase in midbrain DAergic (D2) neurons but then eventually decease in activity
- take weeks (4-6) to have an effect

act on the

• mesolimbic pathway
• mesocorticol pathway
• nigrastriatal pathway
• tubero hypophyseal pathway

Question 3

What is the nigrastriatal pathway?

Answer 3

DAergic neurons project from the substantia nigra to the striatum

is important for initiation/control of voluntary movement
- blocking D2 receptors causes Parkinsonian and extrapyramidal symptoms

parkinsonian
- motor impairment

extrapyramidal symptoms
- dystonia, dyskinesia, akathisia

Question 4

What is the mesolimbic pathway?

Answer 4

DAergic neurons project from the ventral tegmental area to the nucleus accumbens, amygdala and hippocampus

is important in pleasure and reward

• hyperstimulation underlies positive symptoms fo schizophrenia
• D2 antagonism relieves the positive symptoms

Question 5

What is the tubero hypophyseal pathway?

Answer 5

DAergic neurons release DA directly into the hypothalamus which is connected to the pituitary via the hypothalamic pituitary adrenal axis (HPA)
- hypophyseal portal system

DA binds to D2 receptors causing the inhibition of prolactin release
- blocking D2 receptors increases milk production and swelling of breasts
= gynaecomastia

Question 6

What is the difference between typical and atypical antipsychotics?

Answer 6

typical (1st gen)

• mainly antagonise D2 receptors
• treat positive symptoms but are not effective against reducing negative symptoms
• induce severe extrapyramidal side effects

atypical (2nd gen)

• mainly antagonise D2 and 5-HT 2A receptors
• treat positive and negative symptoms
• fewer side effects associated with treatment
• are not more effective at treating extrapyramidal symptoms (same efficacy)

Question 7

Why are antipsychotics dirty drugs?

Answer 7

are able to block many different receptors

• alpha adrenoceptors
• muscarinic receptors
• histamine H1 receptors
• serotonin 5-HT receptor
• dopamine D2 receptors

Question 8

What is the effect of antipsychotics blocking alpha adrenoceptors?

Answer 8

postural hypotension
- reduced noradrenaline binding causes vasodilation (deceased blood pressure)

nasal congestion

hypothermia

Question 9

What is the effect of antipsychotics blocking histamine H1 receptors?

Answer 9

sedation/drowsiness

Question 10

What is the effect of antipsychotics blocking serotonin 5-HT receptors?

Answer 10

weight gain

photosensitisation

Question 11

What is the effect of antipsychotics blocking muscarinic receptors (mAchRs)?

Answer 11

beneficial for treating extrapyramidal symptoms/side effects (caused by the nigrastriatal pathway)

it can have its own side effects = anticholinergic (blocks some parasympathetic activity)

• dry mouth
• blurred vision
• constipation
• urinary retention (micturition)

Question 12

What is the effect of antipsychotics blocking dopamine D2 receptors?

Answer 12

mesolimbic

• acts on the cortex limbic system and suppresses positive symptoms (delusions, halluncination)
• blocks the reward pathway which induces anhedonia and sedation

nigrostriatal
- acts on the striatum (basal ganglia) causing movement disorders
= extrapyramidal and parkinsonian
- acts on the pituitary causing endocrine effect
= increased prolactin results in breast swelling, lactation, impotence and gynaecomastia