Neurobiology of Psychosis Flashcards
What is the largest risk factor for schizophrenia?
Genetics
- high concordance in monozygotic twins or in children where both parents are affected
What perinatal factors may predisposee to schizophrenia?
- 2nd trimester viral illness
- early spring births (due to high rates of illness at this time)
- pre-eclampsia
- foetal hypoxia
- emergency Caesarian section
What type of infection as a child is shown to predispose to schizophrenia?
childhood viral CNS infection
Use of what substances increase the risk of developing psychosis?
Amphetamines
Cocaine
Cannabis
Opiates can cause psychosis. TRUE/FALSE?
FALSE
What signs on CT show poor prognosis in schizophrenia?
Reduced frontal lobe volume
Reduced frontal lobe grey matter
Enlarged lateral ventricle volume
Why is grey matter seen to be reduced in schizophrenia patients?
No neuronal loss
just decreased Arborisation (branching)
Patients with perinatal or childhood environmental risk factors can often identify behavioural, motor and intellectual impairment from early age. TRUE/FALSE?
TRUE
usually from school age
What is the mainstay of treatment in schizophrenia?
Dopamine antagonists
What pathways of the brain involve dopamine
Mesolimbic (reward)
Nigrostriatal
Tuberoinfundibular (prolactin)
What genes are altered in schizophrenia and what is their main impaired function?
Neuregulin
Dysbindin
DISC-1
=> cause impaired branching/ growth of neurones
Give examples of Typical antipsychotics?
Chlorpromazine
Haloperidol
What receptor does haloperidol mainly act on, and what side effects does this cause
D2
=> extra-pyramidal (parkinsons) side effects
What are the reasons for scond generation antipsychotic being branded as “atypical”?
- Less likely to induce Extra-Pyramidal side-effects
- High 5-HT2A to D2 ratio
- Better efficacy against negative symptoms
Give examples of atypical antipsychotics
Olanzapine
risperidone
quetiapine
What is an acute dystonic reaction to antipsychotics?
- occurs after single dose or within 24 hrs
- spasm of particular muscle/ group of muscles
How is an acute dystonic reaction treated?
Stop anti-psychotic OR give anti-cholinergic
What is akathisia?
- Internal restlessness
- patients complains of feeling need to constantly move
- may notice them fidgeting, wriggling or pacing
What is Tardive dyskinesia?
Late onset repetitive mouth movements (involuntary)
e.g grimacing, sticking tongue out, lip smacking
Blocking dopamine receptors causes hyperprolactinaemia. What symptoms can this cause?
Females
amenorrhoea
galactorrhoea
bone density problems
Males
Gynaecomastia
sexual dysfunction
What are the side effects of blocking 5HT2 receptors?
Weight gain
sedation
metabolic syndrome
What are the main symptoms of metabolic syndrome?
Increased abdominal circumference
High BP
High Cholesterol
High Blood Glucose
Some anti-psychotics act on alpha-adrenoceptors. What side effects could this cause?
Postural hypotension
Some anti-psychotics have an anti-muscarinic effect, what does this cause?
Blurred vision Dry mouth Constipation Urinary retention Sedation and confusion
WHat should be considered when choosing an anti-psychotic?
- little difference in efficacy (except clozapine)
- past use? what has worked?
- pre-existing comorbidities?
- patient concerns? side effects?
What is a depot?
Long acting IM injection
can be used for antipsychotics
- used if patients detained and lacking capacity but need tx
OR
- if patients do not wish to comply with daily medication
When is clozapine normally used?
Treatment resistant cases of schizophrenia
3rd line
What are the potential side effects of clozapine?
Myocarditis
Paralytic ileus
Agranulocytosis
How should a patients bloods be monitored when started on clozapine?
Once a week for 6 months
Every 2 weeks for 6 months
Every 4 weeks thereafter
IF STOPPED - 1 month post stopping drug
