L20 - Psychosis Flashcards
Psychosis
Presence of hallucinations or delusions
Hallucinations
Perception without a stimulus
- auditory
- visual
- touch
- taste
- smell
Visual hallucinations
Normally has an organic cause like space occupying lesion
Hypnogogic
- hallucination when going to sleep
Hypnopompic
Hallucinations when waking up
Delusions
Fixed false belief which is unshakeable and outside cultural norms
First rank symptoms of schizophrenia
Auditory hallucinations
Passitivity experiences - not in control of your body
Thought withdrawal, broadcast or insertion
Delusional perception
Somatic hallucinations
Auditory hallucinations
Thought echo - hearing thoughts aloud
Running commentary - voice commentating on one’s actions
Third person - voices conversing with each other about the patient
Passivity experiences
Patient believes that their action or feelings is caused by an external force
Thought withdrawal
Thoughts are being taken out of your mind
Thought broadcast
Everyone knows what the person is thinking
Thought insertion
Thoughts implanted by others
Delusional perception
Attributing new meaning to a normally perceived object normally involving one’s self
Somatic hallucinations
Mimics feelings from inside the body
Positive symptoms
Delusions
Hallucinations
Thoughts disorder
Lack of insight
Negative symptoms
Under activity Low motivation Social withdrawal Emotional flattening Self neglect
Dopamine theory of schizophrenia
- Dopamine concentration too high therefore causes schizophrenia
- Drugs e.g. amphetamines cause the release of dopamine and induced psychotic symptoms
- dopamine antagonists on D2 successfully treat psychosis
4 dopaminergic pathways in the brain
Mesolimbic
Mesocortical
Nigrostriatal
Tuberoinfundibular pathway
Mesolimbic pathway
From: ventral tegmental area
To:
- limbic structures - amygdala, septal area and hippocampal formation
- nucleus accumbens
Overactive in schizophrenia - too much dopamine giving positive symptoms
Mesocortical pathway
From: ventral tegmental area
To: frontal cortex and cingulate cortex
Under active in schizophrenia- negative symptoms
Brain changes in schizophrenia
Enlarged ventricles Reduced grey matter - reduced brain weight Decreased temporal lobe volume Reduced: - amygdala - prefrontal cortex - parahippocampal gyrus - hippocampal formation
Neuropathology of schizophrenia
Decreased pre -synaptic markers
Decreased oligodendrolagia
Decreased thalamic neurones
= aberrant connectivity theory - inappropriate connectivity
Other theories of schizophrenia
Limbic structures - regulating emotional behaviour
Basal ganglia - motor symptoms e.g. catatonia
Typical antipsychotics
- block D2 receptors in all CNS dopaminergic pathways
- main action on mesolimbic and mesocortical pathways
- side effects as affects other pathways e.g Parkinsonism
- good for positive symptoms
Atypical antipsychotics
Lower affinity for D2 receptors
Milder side effects a dissociate rapidly
Also block serotonin receptors
Side effects of atypical antipsychotics
- impaired glucose tolerance - diabetes
- weight gain
- hypercholesterolnaemia - CHD
- prolonged QT - ventricular tachycardia
Nigrostriatal pathway
From: substantia nigra pars compacta
To: striatum
By giving dopamine antagonists there is less dopamine so there is decreased movement
Catatonia
More than 2 weeks of:
- mutism/ stupor
- excitement
- posturing
- negativism
- rigidity
- waxy flexibility
- command automatism
Why do people get catatonia
Less GABA binding so loss of inhibitor effect
Tuberoinfundibular pathway
From: arcuate and periventricular nuclei of the hypothalamus
To: infundibular region of the hypothalamus
Hyperprolactinaemia
Dopamine normally inhibits prolactin release from the pituitary
Dopamine antagonists lower dopamine resulting in higher prolactin
Can cause:
- amenorrhoea
- galactorrhoea
- decreased fertility
- reduced limbic
- osteoporosis/ osteopenia
Difficulties in treating schizophrenia
Lack of insight - don’t believe they are unwell
Medications are often not taken
Alternative methods of medication delvelivery
Orodispersible - dissolve quickly
Short acting IM
Depot injections - long acting and slow
Prognosis of schizophrenia
Earlier someone is treated the better the prognosis
Moderately good long term global outcome - 50%
Good prognosis factors
Absence of family history Good premorbid function Acute onset Mood disturbances Prompt treatment Maintenance of initiative and motivation
Onset in males and females
Males - early 20s
Females - late 20s
Consequences of schizophrenia
Higher mortality High incidences of CVS disease, resp disease and cancer Suicide risk 9x higher 50% have substance misuse High rate of cigarette smoking
