12. Psychosis Flashcards
what is psychosis?
a set of symptoms - not a diagnosis
presence of hallucinations and delusions
define hallucinations
a perception without an acompanying stimulus
in any sensory modality
how can hallucinations be caused by organic pathologies?
if visual hallucinations - can be due to tumour or eye disease
what hallucinations are designed as physiological?
hypnogogic - when going to sleep
hypnopompic - upon waking
define delusions
a fixed, false belief which is unshakeable, outside of cultural norms
what are some common misconceptions of schizophrenia?
- not a split mind
- patient is more dangerous (only 5% of violent crimes commited by those with severe mental illness)
what are some clinical features of schizophrenia?
first rank symptoms - hearing thoughts aloud, running commentary, third person delusions
passivity experiences - belief that an action or feeling is caused by external force
thought withdrawal - belief thoughts are being taken out of the mind
thought broadcast - belief that everyone knows what the patient is thinking
though insertion - belief that thoughts are being implanted by others
delusional perceptions - attribution of a new meaning to a normally percieved object
somatic hallucinations - feeling like they are being touched
how can symptoms of schizophrenia be classified?
positive (adding something) - delusions, hallucinations, thought disorder, lack of insight
negative (taken away) - underactivity, low motivation, social withdrawal, emotional flattening, self neglect
rummarise the pathophysiology of schizeophrenia
dopamine levels, evidence:
drugs that increase dopamine levels(eg: amphetamine) induce psychosis
drugs that antagonise dopamine treat psychosis (D2 especially)
what are some brain changes tht occur in schizoprhrenia?
enlarged ventricles decreased grey matter decreased temporal lobe vol reduced size of limbic structures and prefrontal cortex changes at synapses fewer oligodentrocytes fewer thalamic neruones
what other features might schizophrenics show?
movement disorders - role of basal ganglia
how is schizophrenia treated?
antipsychotics - block D2 receptors throughout the CNS, inhibited in mesolimbic and mesocortical pathways
atypical antipsychotics - lower affinity for D2 receptors so milder side effects, also block 5HT2 receptors (so some action on serotonin systems)
how do side effects of antipsychotics come about?
blocks other pathways such as nigrostriatal - affects movement, causing parkinson like symptoms
dopamine inhibits prolactin, so amenorrhoea, galactorrhoea, decreased fertility, libido and osteoporosis
if schizophrenia is left untrated what may develop?
catatonia - due to involvement of GABA
wghat are some challenges in treating shizophrenia?
patients do not think they are ill - lack insight so can affect compliance with treatment so medication can be given via depot injection