Scizophrenia Flashcards
What is the ICD-10 criteria for diagnosing schizophrenia?
At least 1 of these first-rank symptoms for at least 1month:
- thought echo, thought insertion/withdrawal, thought broadcasting
- delusions of control, influence or passivity, clearly referred to body/limb movements or specific, thoughts, actions or sensations
- auditory hallucinations giving a running commentary/discussing patient between themselves/hallucinatory voices coming from somewhere else in their body
- persistent delusions that are completely impossible
What is thought echo?
Hearing your thoughts as an auditory hallucination
What is thought insertions or withdrawal?
An external force either places or removed your own thoughts from your head
What is thought broadcasting?
The experience that your thoughts are no longer private and can be read/heard by other people
What is the secondar ICD-10 diagnostic criteria if patient does have a first-rank symptom?
At least 2 second-rank symptoms …
- persistent hallucinations in any modality
- thought disorder (incoherent speech due to breaks in flow and/or making up words)
- catatonic behaviour (posturing, waxy flexibility, mutism, stupor, catatonic excitement)
- negative symptoms not due to depression or medications
What are the 4 dopamine projection pathways in the brain?
- Nigrostriatal
- Mesolimbic
- Mesocortical
- Tuberoinfundibular
What are the main dopamine pathways affected in the pathophysiology of schizophrenia?
Nigrostriatal = excess dopamine in associative striatum = positive symptoms/psychosis
Tuberoinfundibular = decreased dopamine =
Where does the nigrostriatal pathway project from/to?
From Substantia Nigra pars compacta (SNc)
To the striatum (putamen and caudate)
Where does the mesolimbic pathway project from/to?
From ventral tegmental area (VTA)
to limbic (ventral) striatum (associated with reward, motivation, mood, memory…)
Where does the mesocortical pathway project from/to?
From VTA
To frontal cortex (specifically the DLPFC, important for cognitive function, emotion etc)
Where does the Tuberoinfundibular pathway project from/to?
From tuberal region
To median eminence (infundibular region at top of pituitary stalk)
What are the 3 functional subdivisions of the striatum?
Sensorimotor (dorsal) striatum
Associative (mid) striatum
Limbic (ventral) striatum
What is the function of the sensorimotor (dorsal) striatum?
Involuntary motor control
What is the function of the associative (mid) striatum?
Learning
Habituation
Memory
Attention
Motivation
Emotion
Volition
What is the function of the limbic (ventral) striatum?
Rewards system of the Brian
What are the 2 divisions of the nigrostriatal pathway?
- SNc to sensorimotor (dorsal) striatum
- SNc to associative (mid) striatum
What are the 2 dopamine receptor families called ?
- Dopamine 1 receptor family (D1, D5)
- Dopamine 2 receptor family (D2, D3, D4)
Where are D1 receptors found?
- motor striatum
- associative striatum
- limbic striatum
- cerebral cortex
Where are D2 receptors found?
- motor striatum
- associative striatum
- limbic striatum
Which dopamine pathways are most effected in schizophrenia?
Nigrostriatal pathway (increased dopamine)
Mesolimbic pathway (normal/slight decreased dopamine)
Which change in dopamine levels correlated with negative symptoms?
Decreased dopamine in ventral striatum = Mesolimbic pathway
What change in dopamine levels correlated with positive symptoms?
Increased dopamine in associative striatum = Nigrostriatal pathway
What is the effect of antipsychotics (D2 antagonists) on
A) positive symptoms?
B) negative symptoms?
A) antipsychotics improve positive symptoms
B) antipsychotics worsen negative symptoms
Name a type of glutamate receptor?
NMDA receptors
