Schizophrenia and affective disorders Flashcards
What are the two types of symptoms of schizophrenia?
positive symptoms - delusions, hallucinations
negative symptoms - impaired communication, cognition and depression
To what extent are genetic factors responsible for Schizophrenia?
Some heritability, high concordance rate for MZ twins however they can be discordant
Genes such as DISC1 that controls neuronal migration during development is believed to play a role
Who was a) the first to describe Schizophrenia and b) the first to describe positive and negative symptoms
a) Kraeplin (1887)
b) Bleuler
What was the first drug therapy discovered for Schizophrenia?
Chlorpromazine, a dopamine antagonist discovered by Laborit in 1952
What brain abnormalities are often seen in those with schizophrenia?
- Enlarged brain ventricles
- Reduced cerebral grey matter with dramatic loss of cortical grey matter in adolescence
- Hypofrontality
What is hypofrontality and what symptoms of schizophrenia is it associated with?
Decrease of NMDA and dopamine in the prefrontal cortex, leading to increased dopamine in midbrain mesolimbic system (dopamine hypothesis)
Associated with negative symptoms
What is the function of atypical antischizophrenia drugs?
- reduce dopamine in the nucleus accumbens (positive symptoms)
- increase dopamine in the prefrontal cortex (negative symptoms)
works as a PARTIAL AGONIST
What gene is likely to be involved in depression?
Gene for serotonin transport, short genes for serotonin transport increase the risk of depression but only if a person experiences stressful life events
What brain abnormalities are seen in people with short serotonin transporter genes?
Reduced volume of amygdala and subgenual anterior cingulate cortex
What brain abnormalities are associated with depression?
- decreased subgenual prefrontal cortex
- reduced inhibition through cingulate cortex following feelings of fear/anger
What is the monoamine hypothesis?
That decreased monoaminergic (serotonin and noradrenaline) activity causes depression
What areas are targeted by deep brain stimulation to treat depression?
- Subgenual anterior cingulate cortex
- Vagal nerve
