1
Q
What is schizophrenia?
A
- A type of major psychoses (madness).
- It has an early onset, prevalent and is a disabling and manic illness.
- It is considered a mental state that is out of touch with reality.
- Abnormalities of perception, thought and ideas
- Profound alteration in behaviour
2
Q
Prevalence of Schizophrenia
A
- Affects up to 1% of population which is relatively high
- No significance influence of culture, ethnicity, background or socioeconomic group
- However, present in urban areas.
- No differences between sexes unlike depression
- Before the illness can be recognised, therefore is often a phase in late teenage years associated with isolation, and social withdrawal.
3
Q
Phases of schizophrenia
A
- The prodrome
- The active/acute phase
- Remission
- Relapse
4
Q
What is the prodrome phase of schizophrenia?
A
- Late teens/early twenties often mistaken for depression or anxiety
- Can be triggered by stress
- Negative symptoms
5
Q
What is the active/acute phase in schizophrenia?
A
- Onset of positive symptoms
- Differentiation of what is and isn’t real is not present
- Hallucinations and delusions
6
Q
What is the remission phase in schizophrenia?
A
- Treatment and returning back to normal
- Schizophreniform is positive symptoms for at least a month but under 6 months before relapse
7
Q
What are the three catergories of Schizophrenic symptoms?
A
Positive
Negative
Cognitive
2 or more symptoms must be persist for at least 6 months
8
Q
What are the positive schizophrenic symptoms?
A
- Increase in abnormal behaviour
- Visual and auditory (See and hear things)
- Somatosensation - feel things that aren’t there
- Delusions - disorted speech
9
Q
What are the negative schizophrenic symptoms?
A
- Decrease in normal behaviour
- Social withdrawal
- Lack of enjoyment and emotion
- Poverty of speech
- Emotional flatness
- Anhedonia - no pleasure in anything
10
Q
What are the cognitive schizophrenic symptoms?
A
- Cognitive defect (can’t process thoughts)
- Impaired memory, attention and comprehension
11
Q
Hallucinations
A
- Perception experiences without stimulus
- Auditory/hearing voices
- Patients may engage with the dialogue with the voices or obey their commands
12
Q
Delusions
A
- A fixed unshakable belief
- Often paranoid or persecutory
13
Q
Potential causes of schizophrenia
A
- Nature
- Nurture
14
Q
Nature causes of schizophrenia
A
Genetics
- Tends to run in families, not directly inherited but can be linked in the family tree e.g. great uncle has it or another distant family member
- Twin studies have shown 50% chance of getting schizophrenia if you have an identical twin that has it
- If it was only caused by genetic factors, there would be a 100% chance between identical twins
- This means that SCZ genes only predisposes you to the disease so other factors must be present
- COMT, DISC1 and GRM3 are some of the genes that predispose someone to the disease
15
Q
What are the genes that predispose someone to schizophrenia?
A
COMT, DISC1 and GRM3
16
Q
Nurture causes of schizophrenia
A
- Pregnancy or birth complications, including low birth weight, premature birth and Asphyxia during birth
- Season of birth -> influenza
- If the mother was in the 1st and/or 2nd trimester in the winter and got the flu, the risk of the baby developing schizophrenia when they are older is higher
- This is why pregnant women are advised to be vaccinated against seasonal flu
- General stress: moving, early love bereavement, loss of job, relationships etc
- Cannabis use in early life as well as amphetamine, cocaine and LSD.
17
Q
Pathophysiology of Schizophrenia
A
- Dopamine hypothesis
- Brain structure differences
- Hypofrontality
- NMDA receptor hypofunction
- Oxidative stress
- Neuroinflammation
18
Q
What are the three stages in the dopamine hypothesis?
A
- Hyperactivity of the mesolimbic pathway
- Hypoactivity of the mesocorticol
- Decreased tuberohypophyseal
19
Q
How does hyperactivity of the mesolimbic pathway affect dopamine?
A
- Hyperactivity of the mesolimbic pathway which is linked to the reward symptom.
- Schizophrenia associated with abnormally high dopaminergic transmission
- Assumed because substances which cause overstimulation of dopamine receptors have similar symptoms to schizophrenia
- Amphetamine and Cocaine have SCZ symptoms and they block the uptake of dopamine
- The blocking of the D2 receptors in the mesolimbic pathway is associated with the antipsychotic effects and decrease in positive symptoms
20
Q
How does hypoactivity of the mesocortical pathway affect dopamine?
A
- Associated with negative symptoms due to loss of cognitive control, motivation and emotion
- Therefore, dopamine levels in the mesolimbic need to be decreased and need to be increased in the mesocortical system
21
Q
How does decreased tuberohypophyseal pathway affect schizophrenia?
A
- Therefore, no prolactin release inhibition and therefore men and women get enlargement of breasts.
22
Q
Brain structure abnormalities in Schizophrenic patients
A
Overall, the brain of a SCZ patient is smaller. There is reduction in grey matter. There is also enlarged lateral ventricles and a smaller hippocampus
23
Q
What is hypo-frontality?
A
Reduced blood flow to the frontal cortex showing hypoactivity of the frontal cortex and therefore there is distorted cognitive function in the SCZ patients
24
Q
Glutamate hypothesis and schizophrenia
A
- Low number of NMDA receptors in the prefrontal cortex of SCZ patients
- NMDA antagonists are ketamine and phencyclidine which causes hallucinations and thought disorders
- NMDA low levels enhance mesolimbic DAegic activity
- Theory is that low levels of glutamate and DA exert excitatory and inhibitory effects on GABAergic striatal neurons projecting to the thalamus and sensory cortex.
- Too much or too little action will disable the gate and allow unwanted sensory information to the cortex.
- Low glutamate is thought to be linked to negative symptoms
25
Serotonin hypothesis
- Increased serotonin levels are linked with SCZ episodes
| - Agonists of serotonin lead hallucinations serotonin activates the DA pathways
26
What is the overall hypothesis of dopamine?
- Over stimulation of mesolimbic D2 receptors
- Under stimulation of mesocortical D1 receptors
- Under stimulation of glutamate NMDA receptors
- Over stimulation of serotonin receptors
27
Typical antipsychotics
- Antagonise D2 receptors
- Takes longer to work
- Mainly used for positive symptoms
- As with most schizophrenic drugs, severe side effects
28
Types of typical antipsychotics
- Chlorpromazine
- Fluphenazine
- Haloperidol
- Flupentixol
29
Atypical antipsychotics
- Antagonise D2 and 5-HT2a receptors
- Better for negative symptoms
- Fewer side effects as less potent D2 antagonists
- Activation of 5HT2a causes hallucinations so help reduce hallucination which is a use for positive symptom
30
Examples of Atypical antipsychiotics
- Clozapine
- Olanzapine
- Risperidone
- Aripiprazole
31
Overall effect of Antipsychiotics
- Binding to D2 receptors causes blockage in the mesolimbic pathway leading to antipsychotic effects and reduces reward/pleasure
- Binding to D2 receptors in the nigrostriatal pathway leading to movement disorders due to movement control such as Parkinsonism
- Binding to D2 receptors in the tubero-hypophyseal pathway leads to increased prolactin production due to no inhibition and therefore breast enlargement
- Binding to muscarinic receptors leads to blurred mouth, blurred vision and constipation, as well as urinary retention
- Binding to the adrenoceptors leads to hypotension and other CVS problems
- Binding to other receptors can lead to weight gain, sedation
Neuro
flashcards
Decks in class (20)
# Cards
-
Introduction to Clinical Neuroscience52
-
Structure of the Nervous System (Cranial Nerves)70
-
Neurons and Glia66
-
Glutamate57
-
GABA and Glycine48
-
Monoamines104
-
Neurohormones89
-
Vision82
-
The Chemical Senses46
-
Auditory and Vestibular Systems79
-
Sleep53
-
Somatosensation84
-
Motivation61
-
Learning and Memory60
-
Control of Movement41
-
Depression48
-
Emotion35
-
Anxiety41
-
Schizophrenia31
-
Language34
