L14 - Biological basis of Schizophrenia

Question 1

What makes Sz a complex disorder?

Answer 1

It has a wide and diverse range of symptoms

Cause unknown

It’s response to treatment is often unsatisfactory

Question 2

What are the 3 main symptoms categories of Sz?

Answer 2

Positive

Negative

Cognitive

Question 3

What are positive symptoms of Sz?

Answer 3

Hallucinations

Delusions

Thought disorder

Question 4

What are negative symptoms of Sz?

Answer 4

Emotional flattening

Anhedonia (inability to feel pleasure)

Avolition (Lack of motivation/ ability to start activity)

Withdrawal

Motor/ behavioural abnormalities like catatonia

Question 5

what are cognitive symptoms of Sz?

Answer 5

Impairments in attention, memory and executive cognitive function

Question 6

What diagnostic tools are used for diagnosing Sz?

Answer 6

DSM-5-V (USA)
International Classification of Diseases - ICD (Europe)

Question 7

What are key diagnostic criteria for Sz?

Answer 7

Symptoms such as thought insertion, delusions, hallucinatory voices and catatonia persisting for more than a month

Question 8

What are exclusion criteria for Sz diagnosis?

Answer 8

Mood disorders, drug use and neurological conditions

Question 9

What is the prevalance rate of Sz?

Answer 9

Approx. 0.5% (5 per 1000 people surveyed per year)

Question 10

At what age does Sz typically onset?

Answer 10

Late adolescence to early adulthood (between 20-39)

Question 11

How do genetic factors influence Sz risk?

Answer 11

Family history significantly increases risk, with higher concordance in MZ twins (approx. 40-60%) compared to DZ twins (approx 10-15%)

Question 12

What are environmental risk factors for Sz?

Answer 12

Prenatal exposure to viruses, pregnancy/ delivery complications, and social factors like family dynamics

Question 13

What structural brain changes are associated with Sz?

Answer 13

Reduced temporal lobe volume

Enlarged ventricles

Hypofrontality (reduced frontal cortex activity)

Question 14

What’s the dopamine hypothesis of Sz?

Answer 14

Sz may be associated with increased dopamine function, particularly linked to positive symptoms

Question 15

How do amphetamines and dopamine antagonists relate to Sz?

Answer 15

Amphetamines mimic positive symptoms

Dopamine antagonists alleviate them

Question 16

What role does serotonin play in Sz?

Answer 16

Increased serotonin function may be linked to Sz, supported by drug-induced psychosis studies (e.g., LSD)

Question 17

What’s the glutamate theory of Sz?

Answer 17

Decreased glutamate function, evidenced by reduced glutamate levels and receptor changes.

This may contribute to symptoms

Question 18

How do positive symptoms relate to brain function?

Answer 18

They may result from impaired function in the temporal lobes

Question 19

How do negative and cognitive symptoms relate to brain function?

Answer 19

They may result from prefrontal cortex dysfunction and disconnection between temporal and frontal lobes

Question 20

What is the role of serotonin-dopamine antagonists in Sz treatment?

Answer 20

They treat both positive and negative symptoms by modulating multiple neurotransmitter systems

Question 21

What are examples of typical antipsychotics and how do they work?

Answer 21

Dopamine D2 receptor antagonists e.g., Chlorpromazine

Treat positive symptoms but have severe motor side effects

Question 22

What are typical antipsychotics less effective negative symptoms?

Answer 22

they may exacerbate negative symptoms by reducing dopamine function in the mesocortical pathway

Question 23

What are extrapyramidal side effects?

Answer 23

Severe motor side effects that resemble Parkinson’s disease caused by dopamine blockade in the nigostriatal pathway

Question 24

What makes clozapine an atypical antipsychotic?

Answer 24

It has a fewer motor side effects, treats negative symptoms but requires blood monitoring due to risks like leukopenia

Question 25

What is the advantage of atypical antipsychotics?

Answer 25

They act on dopamine and serotonin receptors, reducing both positive and negative symptoms with fewer motor side effects.

Question 26

What are the limitations of atypical antispychotics?

Answer 26

They don't work in all patients, can cause side effects and may take longer to act.

Question 27

What are common issues with antipsychotic treatment compliance?

Answer 27

Adverse side effects often lead to medication miscontinuation and relapse

Question 28

What's the relapse rate for untreated Sz?

Answer 28

approx 10% per month after discontinuing treatment

Question 29

What are psychological therapy options for SZ?

Answer 29

CBT Family therapy Particularly effective when combined with medication

Question 30

What is the prognosis for Sz without Pharmacological intervention?

Answer 30

Approx 20% of parients show near-full recovery

Question 31

How does pharmacological treatment improve prognosis?

Answer 31

Recovery rates rise to approx 50% with antispsychotic use

Question 32

Why is reducing antipsychotic side effects an important goal?

Answer 32

To improve compliance and reduce relapse rates in patients.

Question 33

How does the serotonin theory relate to schizophrenia?

Answer 33

Increased serotonin function, supported by the effects of LSD, may contribute to symptoms.

Question 34

How does the glutamate theory explain schizophrenia?

Answer 34

Decreased glutamate levels and receptor changes are linked to symptoms, although data is inconsistent.

Question 35

What evidence supports the glutamate theory of schizophrenia?

Answer 35

Reduced glutamate in cerebrospinal fluid, increased cortical glutamate receptors postmortem, and decreased glutamate uptake sites in the cingulate cortex.

Question 36

What is the main limitation of the dopamine hypothesis?

Answer 36

It cannot account for negative and cognitive symptoms of schizophrenia.

Question 37

How do temporal lobe deficits contribute to schizophrenia symptoms?

Answer 37

Impaired temporal lobe function is associated with positive symptoms like hallucinations and delusions.

Question 38

How do frontal lobe deficits contribute to schizophrenia symptoms?

Answer 38

Impaired prefrontal cortex function is linked to negative and cognitive symptoms.

Question 39

What is the "disconnection syndrome" in schizophrenia?

Answer 39

It refers to inappropriate communication between temporal and frontal lobes, contributing to symptomatology.