Schizophrenia and psychosis

Question 1

Schizo facts

Answer 1

1% prevalence
15 years
heterogenous
more prevalent in men than women
higher suicide rate - higher morbidity

Question 2

Positive symptoms

Answer 2

Delusions
hallucinations
disorganized thinnking/ speech
disorganized behaviour
lack of insight - unaware that delusions or hallucinations that arent real.

Question 3

Negative symptoms

Answer 3

Blunted affect
Alogia - reduced speech
Avolition - lacking motivation
Anhedonia - lack of pleasure

Question 4

Cogntive symptoms

Answer 4

Impairments in attention - working memory, verbal fluency, motor function.
Pre frontal cortex dorsolateral dysfunction linked to poor memory.

Question 5

Causes of psychosis

Answer 5

Schizophrenia
Bipolar disorder
Severe stress/anxiety
severe depression
lack of sleep
encephalitis - inflammation of the brain
can also occur in some medical conditions

Question 6

Epidemiology - environmental factors

Answer 6

Urban populations affected more
birth complications eg premature
seasonal influences of birth month - earlier in year more likely
famines
drug use - cannabis and amphetamines

Question 7

Gentetics

Answer 7

More common on relatives of those with SZ
48% concordance rate identical twins

Question 8

structure changes of brain

Answer 8

Changes in brain structure - ventricular enlargement
Medial temporal lobe reduction

Question 9

Neurotransmitter hypothesis

Answer 9

dopamine
glutamate
Antipsychotic drugs block funtion of d2 dopamine receptors - chlorpromazine
side effects include parkinsonian symptoms- tremors

Question 10

Dopamine imbalance evidence

Answer 10

Too much dopamine signalling in striatum
not enough in pre frontal cortex
BUT this only accounts for positive symptoms

Question 11

Aberant salience hypothesis

Answer 11

Normally dopamine signals when important or salient events occur in environment.
Dopamine release in dorsal striatum - novelty and intensity
dysregulation in dorsal striatum - causes irrelevant stimuli to become salient - formation of delusion

Question 12

Glutamate hypothesis

Answer 12

Hypofunction LOW - NMDA receptor antagonists can cause psychosis state + negative symptoms of SZ - eg ketamine and PCP.
NMDA is a glutamate receptor.

Question 13

Genetic risks

Answer 13

Common variants with very small effect size
Rare disease variants with large effect size
NO deterministic variants of genes