12.2 Psychosis and Schizophrenia Flashcards
What is psychosis?
Set of symptoms, not a diagnosis
Presnce of hallucinations or delusions
What is a hallucination?
- Perception without an accompanying stimulus
- In any sensory modality
- Visual hallucinations often caused by organic pathologies e.g. tumour, eye disease
What hallucinations are not pathological?
Hypogogic- experienced when going to sleep
Hypnopompic- experienced upon waking
What is a delusion?
Fixed, false belief which is unshakeable
Outside of cultural normality
What is the difference between hebephrenic, paranoid and simple schizophenia?
Hebephrenic
-Indifferent to environment
-Aytpical emotion charactised by inappropriate laughter
Paranoid
-Delusions and hallucinations
-Negative symptoms
Simple
-Social withdrawal
-Apathy (lack of interest, concern or enthusiasm)
-Paucity of speech
-Decline in performance
What are some misconceptions about schizophrenia?
Not split mind
Patients no more dangerous than any other patient
What are the first rank symptoms of schizophrenia?
Auditory hallucinations
-Thought echo- hearing thoughts aloud
-Running commentary
-Third person- multiple voices talking about patient
Passivity experiences
-Belief that an action or feeling is caused by external force
Thought withdrawal, broadcast or insertion
-Thought withdrawal- belief that thoughts are being taken out of the mind
-Thought broadcast- belief that everyone knows what patient is thinking
-Thought insertion- belief that thoughts are being implanted by others
Delusional perceptions
-Attribution of a new meaning to a normally perceived object
Somatic hallucinations
Sense of being touched when no one is there
What symptoms can be classified as postivie or negative in schizophrenia?
Positive- something added
-Delusions
-Hallucinations
-Thought disorder
-Lack of insight
Negative- something taken away
-Underactivity
-Low motivation
-Social withdrawal
-Emotional flattening
-Self neglect
What is the dopamine theory for schizophrenia?
Increased levels of dopamine lead to schizophrenia
Which dopamine pathway is overactive in schizophrenia?
Mesolimbic
What evidence is there for the involvement of dopamine in schizophrenia?
- Drugs that increase dopamine levels induce psychosis e.g. amphetamines
- D2 antagonists treat psychosis
Where are D2 receptors not found in the brain?
Neocortex
What structural brain changes may be present in schizophenia?
- Enlarged ventricles
- Decreased grey matter
- Decreased temporal lobe volume
- Reduced size of limbic structures and prefrontal cortex
- Changes at synapses
- Fewer oligodendrocytes
- Fewer thalamic neurones
Possible role of basal ganglia as some schizophrenics show movement disorder features
What is the typical treatment of schizophrenia?
Typical antipsychotics which block D2 receptors throughout CNS
Antipsychotic action from inhibition of mesolimbic and mesocortical pathways
Side effects come from blocking other pathways e.g. nigrostriatal- parkinsonian features as decreased thalamic activation
How do atypical antipsychotics work?
Lower affinity for D2 receptors than typicals ergo milder effects
Also block 5HT2 receptors, so can affect serotonin systems
