115b - Schizophrenias

Question 1

What is the general mechanism of action of every antipsychotic medication?

Answer 1

Inhibit dopamine signaling

(Dopamine signaling is implicated in both positive and negative symptoms of schizphrenia)

Question 2

What is a delusion?

Answer 2

Firmly held, fixed, false belief

Can be bizzare or non-bizzare

(Bizzare violates the laws of physics; non-bizzare is physically possible)

Question 3

Dopamine dysregulation in the mesocortical dopamine tract results in [positive/negative] symptoms

Dopamine dysregulation in the mesolimbic dopamine tract results in [positive/negative] symptoms

Answer 3

Dopamine dysregulation in the mesocortical dopamine tract results in negative symptoms

Dopamine dysregulation in the mesolimbic dopamine tract results in positive symptoms

Question 4

What is the most common psychotic disorder?

Answer 4

Schizophrenia

Question 5

What changes can be seen in the brain of a person with schizophrenia?

Answer 5

• Volume loss
• Changes in interneurons
• Enlarged ventricles
• Thalamic and hippocampal changes

No neurodegeneration!!

Schizophrenia is caused by abnormal neuronal migration during development, not neurodegeneration

Affects both white and grey matter

Question 6

What are the diagnostic criteria for schizophrenia?

Answer 6

2+ of the following for >6 months, resulting in marked impairment in role function

• Delusions
• Hallucinations
• Disorganized speech
• Grossly disorganized or catatonic behavior
• Negative symptoms
  
  • Removal of traits that animate a person

Question 7

What is the difference between a positive symptoms and a negative symptom of schizophrenia?

List some examples of each

Answer 7

• Positive sypmtom = new things overlaid on normal psyche
  
  • Delusions
  • Hallucinations
  • Disorganized speech
  • Disorganized or catatonic behavior
• Negative symptom = absence of normal behaviors
  
  • Apathy
  • Affective flattening
  • Alogia
  • Avolition
  • Anhedonia

Question 8

Which neurotransmitter is implicated in patients with schizophrenia and psychosis?

Answer 8

Dopamine

• Dysregulation in the mesolimbic dopamine tract -> positive symptoms
• Dysregulation in the mesocortical dopamine tract -> negative and cognitive symptoms

Serotonin, NMDA are likely also involved

Question 9

Describe the pathophysiology of schizophrenia

Answer 9

Impaired neuronal migration during development

• Genes/toxins/hypoxia influence…
• Neuronal formation, migration, synaptogenesis, synaptic pruning, resulting in…
• Functional anatomical disruption, resulting in…
• Impairment in 1+ second-order cognitive processes
• This results in the symptoms of schizophrenia, around age 18-25

NOT neurodegenerative

Question 10

What are the risk factors for schizophrenia?

Answer 10

• Genetic factors contribute the most risk
• Environmental factors: Mother experiences during early neurogenesis or in the prenatal period
  
  • Fetal hypoxia, birth trauma
  • Maternal infection
  • Winter birth months
  • Low SES
  • Extreme stress