19 - Psychosis Flashcards
What is the definition of psychosis?
Presences of hallucinations or delusions but patients have a lack of insight (don’t believe they are unwell)
This is not a diagnosis, it is symptoms
What is a hallucination?
- Perception of a stimulus without a stimulus e.g hearing, feeling, seeing
- Visual are often due to a problem with the brain or the eyes
- Normal to have hallucinations when going to sleep or waking up
What is a delusion?
A fixed false belief that is unshakeable and outside of cultural norms, e.g may think being spied on by the police
What are some different types of psychosis?
- Schizophrenia
- Drug induced
- Affective
- Post partum
What are the symptoms (first rank) of schizophrenia?
Thought withdrawal: patient believes someone is taking thoughts from their mind or broadcasting them
Delusional perceptions: seeing something and giving it a new meaning, e.g red traffic light means aliens are coming
Passivity experience: patient believes their body is being moved by an external force
Somatic hallucinations: patient can feel their insides moving
What are some of the different types of auditory hallucinations?
- Thought echo: hearing their thoughts echoed back to them
- Running commentary: someone is commenting on their actions e.g he is brushing his teeth and now sitting down
- Third person: voices referring to patient in third person and conversing with each other about the patient
What is thought withdrawal?
What are some other symptoms of schizophrenia apart from the first rank ones?
Often patients that are treated can be left with the negative symptoms
What are some organic causes of psychosis?
- Delirium caused by infection
- Hypercalcaemia
- Acute drug/alcohol intoxication (amphetamines causing release of dopamine)
- Post-ictal psychosis
- Hyperthyroidism
- Steroids - L-Dopa
iWhat is the pathophysiology behind schizophrenia in general?
- Too high dopamine binding to D2 receptors
- Overactive mesolimib pathway and underactive mesocortical pathway
What is the mesolimbic and mesocortical pathway?
What are some of the brain changes that occur in a schizophrenic patient?
What is the neuropathology of schizophrenia?
- Decreased pre-synaptic markers
- Decreased oligodendroglia
- Fewer thalamic neurones
Theory of aberrant connectivity
Apart from changes in the dopamine pathway, what other areas in the brain are affected in schizophrenia?
How is schizophrenia treated pharmacologically?
Typical Antipsychotics: (e.g haloperidol)
- Block D2 receptors in all 4 dopaminergic pathways but mainly mesolimbic and mesocortical
- Side effects from D2 antagonists, e.g parkinsonism
Atypical Antipsychotics (e.g clozapine)
- Lower affinitity for D2 receptors so fewer side effects
- Also block 5HT2 receptors
What are some of the side effects of antipsychotics?
Typical: parkinsonism (as involvement of substantia nigra) , get rid of positive symptoms but not negative
Atypical: impaired glucose tolerance, diabetes, weight gain, prolonger QT, hypercholesterolaemia, galactorrhea
Sexual dysfunction side effects due to lack of dopamine to inhibit prolactin production so hyperprolactinaemia
Why do we get Parkinsonism if we overtreat a patient with a typical antipsychotic?
- Decreased dopamine so increased inhibition on the thalamus so less glutamate going to excite the cortex
What can happened to the movement of untreated schizophrenic patients and why does this occur?
Catatonia
- Less GABA binding so loss of inhibitory effect (think about main pathway diagram)
- Rare because we treat early
What is the final dopaminergic pathway not mentioned?
What are some good prognostic factors when diagnosed with schizophrenia?
Early treatment better prognosis
What are some negative prognoses associated with schizophrenia?
- Mortality 2x general population
- Shorter life expectancy
- Higher incidence of CVS, Resp Disease and cancer
- Higher suicide risk and death from violent incidents
- Higher rate of substance misuse and cigarette smoking
When should you be careful prescribing the mood stabiliser sodium valproate?
- To women of child bearing age as this drug affects folate synthesis so can cause neural tube defects if they fall pregnant
- Should not prescribe to these patients unless they are involved in a pregnancy prevention programme
Jim is being treated with an IM injection of antipsychotic, he has started to experience some unpleasant involuntary movements, what are these caused by?
Acute dystonia found in early treatment with antipsychotics
Can treat by giving anticholinergics and antihistamines
What are the ICD-10 criteria for OCD diagnosis?
What are the different subtypes of schizophrenia?
Deep brain stimulation of the subthalamic nucleus in OCD patients will cause what effect?
Increased excitation of globus pallidus internus and substatia nigra pars reticulata
What is hebephrenic schizophrenia?
Shallow and inappropriate emotional responses, foolish or bizarre behaviour
