Session 12: Psychosis Flashcards
Definition of psychosis.
Presence of hallucinations or delusions
(It is not a diagnosis in itself)
What are hallucinations?
Perception of a stimulus without there being a stimulus.
Can be in any sensory modality
Give examples of normal hallucinations
Hypnogogic (hearing your name called when going to sleep e.g.)
Hypnopompic (hearing your name called when waking up e.g.)
What are delusions?
Fixed false belief which is unshakeable and outside the cultural norm.
First rank symptoms of schizophrenia
Auditory hallucinations
Passivity experiences
Thought withdrawal, broadcast or insertion
Delusional perceptions
Somatic hallucinations
Give examples of types of auditory hallucinations in schizophrenia.
Thought echo (hearing thoughts aloud)
Running commentary
Third person voices
What are passivity experiences?
Patient believes an action or feeling is caused by an external force.
E.g.
MI5 have been moving my leg
What is thought withdrawal?
Thought are being taken out of the mind
What is though broadcast?
Everyone knows what the person is thinking
What is thought insertion?
Thoughts implanted by others
What are delusional perceptions?
Attribution of new meaning usually in the sense of self-reference to a normally perceived object.
An example is:
Traffic lights went red and I knew this was a sign that aliens were going to land soon.
Positive symptoms of schizophrenia
Delusions
Hallucinations
Thought disorder
Lack of insight
(These are added symptoms)
Negative symptoms of schizophrenia.
Underactivity
Low motivation
Social withdrawal
Emotional flattening
Self neglect
(symptoms that are taken away from patient)
Dopamine theory of schizophrenia.
Drugs like amphetamines which cause the release of dopamine agonists induces schizophrenic psychotic symptoms.
All medications that antagonise DA receptors help treat psychosis and those with the strongest affinity to D2 receptions are most clinically effective.
2 main pathways involved in schizophrenia
Mesolimbic pathway
Mesocortical pathway
Explain the mesolimbic pathway
From the ventral tegmental area to the limbic structures and the nucleus accumbens.
What is different about the mesolimbic pathway in schizophrenia?
It is thought to be overactive
Explain the mesocortical pathway.
From the ventral tegmental area and the goes to the frontal cortex and the cingulate cortex.
What is different about the mesocortical pathway in schizophrenia?
It is thought to be underactive
Brain changes in schizophrenia (macro).
Enlarged ventricles
Reduced grey matter
Decreased temporal lobe volume
Reduced hippocampal formation, amygdala, parahippocampal gyrus and prefrontal cortex.
Neuropathology of schizophrenia
Decreased presynpatic markers
Decreased oligodendroglia
Fewer thalamic neurons
Give other theories of schizophrenia.
Other limbic structure involvment - emotional behaviour
Basal ganglia involved since untreated patients can present with motor symptoms
Treatment of schizophrenia.
Typical or atypical antipsychotics
Action of typical antipsychotics.
Block D2 receptors in all CNS dopaminergic pathways.
The main action is on mesolimbic and mesocortical pathways.
Side effects arise from antagonising D2 receptors in other pathways.
