Schizophrenia

Question 1

Positive symptoms

Answer 1

Hallucinations (auditory)
Delusions (of grandeur, persecution)
Disorganised speech
Catatonic behaviour

Question 2

Negative symptoms

Answer 2

Social withdrawal
Reduced expression of emotion
Cognitive impairment

Question 3

What is schizophrenia

Answer 3

A thought disorder involving a loss of contact with reality, disruptions in mood, perception, thoughts & movement.

Question 4

What are the course of the symptoms like in schizophrenia

Answer 4

can spontaneously remit - relapsing/remitting

can be chronic

Question 5

Proportion of treatment resistant schizophrenia

Answer 5

~30%

Question 6

Risk factors of schizophrenia

Answer 6

Strong but not invariable genetic component (identical twins 48%)
Partly environmental - higher incidence in urban areas, maternal malnutrition, birth defect, viral infection, autoimmune process, marijuana

Question 7

Dopamine hypothesis of schizophrenia

Answer 7

Hyperactivity in the mesolimbic (VTA > limbic area) pathway causes the positive symptoms
Hypoactivity in the mesocortical (VTA > cortex) pathway causes negative symptoms

One gets over-active the other one gets under-active, vice versa; feedback loop between two pathways.

Question 8

Problems with the dopamine hypothesis

Answer 8

• Clinical latency of neuroleptics - take weeks to work so secondary effects of blocking D2 receptors are important
• Less effective on negative symptoms so hypothesis is too simplistic

Question 9

The glutamate hypothesis

Answer 9

Schizophrenia reflects diminished NMDA receptor activation in the brain.

Question 10

Evidence for the glutamate hypothesis

Answer 10

Phencyclidine (PCP) and ketamine both inhibit NMDA receptors and give positive and negative symptoms of schizophrenia including hallucinations and paranoia.

Question 11

Not all NMDA inhibitors give schizophrenic symptoms, the reason suggested for this

Answer 11

PCP & Ketamine do because they do not interfere with glutamate binding to the receptor, instead they enter the channel and clog the pore. For the channel to be open to clog, glutamate must be bound /receptor must be active. Maybe drug effect mediated by a select population of neurones with tonic NMDA receptor activation (seen in cortex).

Question 12

% of population with schizophrenia

Answer 12

1%

Incidence low, prevalence high as no cure

Question 13

How is schizophrenia diagnosed

Answer 13

Positive symptoms needed to make diagnosis even though negative ones probably pre-date them