09 Schizophrenia - Neurobiological Hypotheses

Question 1

Schizophrenia - symptoms

Answer 1

• positive symptoms: delusions, hallucinations, delusion of control
• negative symptoms: blunted affect, alogia, avolition, asociality, anhedonia
• cognitive symptoms: memory, attention, executive functions

Question 2

recovery in schizophrenia

Answer 2

• 13.5% median recovery (1 out of 7)
• higher recovery in poorer countries
• no increase in recoveries despite major changes in treatment options in recent decades

Question 3

symptom trajectories in first-episode psychosis

Answer 3

• remitting-improving (58.5%)
• persistent (30.6%)
• late decline (5.6%)
• late improvement (5.4%)
  symptomatic course is heterogeneous and intrinsically difficult to predict

Question 4

schizophrenia - risk factors

Answer 4

• ethnicity / ethnic minority
• migration experiences
• urbanicity
• parental age > 45
• born in winter

Question 5

neurodevelopmental hypothesis of schizophrenia

Answer 5

• abnormalities in neurodevelopment + second-wave hits sometimes sufficient for development of schizophrenia

Question 6

altered plasticity and dysconnectivity & dopamine dysfunction - associations

Answer 6

• altered plasticity and dysconnectivity: cognitive deficits, negative symptoms
• dopamine dysfunction: aberrant saliency, positive symptoms

Question 7

altered excitation/inhibition balance hypothesized circuit mechanism

Answer 7

• imbalance between excitatory glutamate system and inhibitory GABA system
• dysfunction of the midbrain leads to overactivity of dopamine system

Question 8

working memory impairment in psychosis

Answer 8

• worse performance in schizophrenia patients with medium to large effect sizes
• in high-risk subjects who later develop psychosis
• dlPFC dysfunction (hypoactivity)
• no group difference for glutamate concentration in dlPFC
• interaction effect of group by MRS glutamate

Question 9

dopamine hypothesis

Answer 9

• effectiveness of antidopaminergic medication
• psychotomimetic effect of dopaminergic drugs
• D2 occupancy is contributing factor for the mechanism of antipsychotic effect in SCZ for some but not all antipsychotic medications
• more dopamine released in schizophrenia patients
• if D2 receptor occupied, symptoms get better
• increase in psychotic symptoms was associated with the amount of dopamine released
• dopaminergic dysfunction is associated with positive symptoms
• elevated striatal dopamine function in schizophrenia
• aberrant saliency