Schizophrenia Flashcards
what are the 3 categories of Schizophrenia Symptoms
positive, negative and cognitive
what are positive symptoms of Schizophrenia
Psychosis: delusions, hallucinations
disorganised speech, distortions in language and communication.
what are delusions
misinterpretation of perception or experience
secret messages, poisoned, sexual/religious/scientific delusions, conspiracy, espionage
what are hallucinations
sensing things that aren’t there
visual: people
auditory: hearing speech that isn’t said
tactile: itching skin
olfactory: smell of gas and rotting meat
what are negative symptoms
reduction of normal functions
blunted affect
dysfunction of motivation
anhedonia: dysfunction of pleasure
what are cognitive symptoms
attentional problems (planning, maintaining goals, problem solving)
what is the etiology of schizophrenia
positive: the mesolimbic dopamine pathway
negative: the mesocortical pathway
too few GABA in the thalamus
Explain the dopamine hypothesis
Positive symptoms (psychosis: delusions and hallucinations) arise because of hyperactive DA neurons in mesolimbic circuit, too much DA in ventral striatum
arises in the nigrostriatal, mesolimbic, mesocortical and tuberinfundibular areas of the brain
(3/4 of the brain circuits)
treatment: Classic antipsychotics dopamine D2-receptor antagonists
what is the difference in DA in the mesolimbic and mesocortical pathway
mesolimbic: too much DA in nucleus accumbens
mesocortical: too few DA to PFC
Explain the glutamate hypothesis
NMDA receptor hypofunction, acts like ketamine.
- glutamate stimulates NMDAR
- NMDAR hypoactive
- less DA release in PFC
- negative and cognitive symptoms
Divide positive, negative and cognitive functions in these pathways
Dopamine: positive
Glutamate: negative and cognitive
explain dopamine pathway in schizophrenia
- hypoactive glutamate
- hypoactive NMDAR
- no depolarisation
- less signalling GABA
couple both pathways
NMDA-R hypofunction causes hypoactivation mesocortical DA pathway = coupling glutamate- and dopamine hypotheses
why is there decreased GABA in the thalamus of schizophrenic patients
- excess DA inhibits GABA
2. NMDAR hypofunction
what is the consequence of decreased GABA
less filtering sensory signals, sensory overload
