Structure and Function - Week 7 - Schizophrenia

Question 1

Describe schizophrenia (5)

Answer 1

Major CNS disorder
Debilitating
Most severe & least understood psychiatric disorder
Symptomatic onset in early adulthood & persists throughout life
No cure; drugs manage the disease

Question 1

What is the problem with schizophrenia (4)

Answer 1

Not a single disease, but spectrum of disorders

Strikes young people with little warning (20-39 first presentation)

Expensive to health service

No gross CNS pathology- 10% die by suicide

Question 2

Describe onset of symptoms between men and women for schizophrenia (2)

Answer 2

Peak onset is 15-25 yrs in males, 25-35 yrs in female & post-menopause

Men and women affected equally overall

Question 3

Describe the two symptoms of schizophrenia (2)

Answer 3

Split into ‘positive’ & ‘negative’ symptoms with cognitive impairment

Question 4

Describe the positive symptoms of schizophrenia (4)

Answer 4

Hallucinations; aural & visual (especially aural – voices)

Delusions – persecution complex (paranoia)

Inappropriate emotions and actions

Often presented in younger patients more

Question 5

Describe the negative symptoms of schizophrenia (4)

Answer 5

Apathy
Depression
Social incompetence
Loss of insight (can’t recognise own illness)

Question 6

Describe the cognitive symptoms of schizophrenia (3)

Answer 6

Attention, memory, executive functions
Older patients often present with type II
Positive symptoms usually give way to negative with time

Question 7

What do the symptoms of Schizophrenia lead to (4)

Answer 7

Functional Impairments
Work
Interpersonal relationships
Self-care

Question 8

What are the different risk factors of schizophrenia (3)

Answer 8

Genetic
Environmental
Combination of factors

Question 9

Describe the genetic risk factors of schizophrenia (3)

Answer 9

Where has been surveyed, consistent ~1.3% rate in population

Heritable risk factor: 10% if close relative, 46% if both parents affected, 50% concordance rate in identical twins

Question 10

Describe the environmental risk factors of schizophrenia (3)

Answer 10

Toxins, viruses, brain damage
More common in those born in winter
More common in those who suffered difficulties at birth

Question 11

Describe the combinational risk factors of schizophrenia (3)

Answer 11

Likely that environmental factors determine whether genetic predisposition is expressed – epigenetics?

Question 12

Describe the known biology of schizophrenia (3)

Answer 12

Glutamate systems appear underactive
Dopamine systems appear overactive
Appearance of symptoms dependant on developmental brain maturation – different to other disorders where age=decline

Question 13

Describe neurochemistry pf schizophrenia (4)

Answer 13

Associated changes in neurochemistry with neuroanatomy (as expected)
Difficulty in determining which precedes which
Main two implicated systems are dopamine and glutamatergic
5-HT thought to be involved

Question 14

Describe the dopamine hypothesis of schizophrenia (4)

Answer 14

Abuse of stimulants leads to schizophrenic-like psychosis via release of dopamine

Schizophrenia linked to a hyperactive and hypoactive DA system (DA mesolimbic pathway= +VE & DA mesocortical = -VE)

Question 15

Describe glutamatergic role in schizophrenia (4)

Answer 15

Main transmitter for pyramidal cells; sources of efferent, interconnecting pathways of cerebral cortex & limbic = regions implicated in schizophrenia

Genetic factors affecting signalling of ion channel receptors and GPCR types

Usually resulting in hypofunction of glutamate neurotransmission (directly relevant for –ve symptoms - PCP)

Glutamate receptor antagonists (ketamine, phencyclidine) cause +ve & -ve symptoms

Question 16

Describe the classification of antipsychotics (2)

Answer 16

Can classify by chemical structure but is mainly by broader classification:
- “typical” & “atypical”, effectively old and new respectively

Question 17

Describe typical antipsychotics (4)

Answer 17

Selective D2/D3 antagonists
Treat +ve symptoms
No effect on -ve symptoms
No effect on cognitive symptoms

SERIOUS SIDE EFFECTS

Question 18

Describe atypical antipsychotics (4)

Answer 18

D2/D3 antagonism & other affinities
Treat +ve symptoms
Limited effect on -ve symptoms
Limited effect on cognitive symptoms

SERIOUS SIDE EFFECTS

Question 19

Describe the mechanism of action of antipsychotics (5)

Answer 19

Blockade (antagonism) of DA receptors, especially D2 but possibly D4
single dose = CNS excitation
single high dose = manic behaviour
chronic abuse = paranoia, delusions (responds to APs)

Question 20

Describe antipsychotic effects on type 1 schizophrenia (2)

Answer 20

Reasonable response but delayed 2-3 weeks before insight returns

Question 21

Describe antipsychotic effects on type 2 schizophrenia (2)

Answer 21

Poor response to most APs, clozapine reportedly ‘effective’

Question 22

Describe some antipsychotic side effects (3)

Answer 22

Extrapyramidal Syndrome (EPS)
DA block equivalent to DA loss
Tardive Dyskinesia