Schizophrenia Flashcards
Occording to some guy what are the 4 main problems with schizophrenia?
- Its presentation is diverse
- Its cause is unknown
- Its response to treatment is limited
- Its symptoms are numerous
Define psychosis
The inability to distinguish between a subjective experience and external reality associated with lack of insight
Define a delusion
A fixed false belief which is out of keeping with religious and cultural normals and is unshakable despite evidence to the contrary
Define hallucinations
A perception in the absence of external stimuli
What are the 3 characteristic symptoms of psychosis?
Thought disorder
Hallucinations
Delusions
What are the different types of schizophrenia?
Paranoid
Hebrephrenic
Catatonic
Residual
What is paranoid schizophrenia?
A form of schizophrenia where delusions and hallucinations predominate.
What is catatonic schizophrenia?
Catatonia describes the phenomenon of a patient remaining still in a set position
In this form of schizophrenia they are withdrawn and mainly negative symptoms predominate
What is hebrephrenic schizophrenia?
Associated with though disorganisation, disturbed behaviour (often silly) and fast affect.
What are the first rank symptoms of schizophrenia?
Perceptional delusions (normal perception interpreted in a delusional way) Auditory hallucinations (3rd person, running commentary, voices arguing) Delusions of passivity (passivity of volition, somatic passivity, impulse passivity) Delusions of though control (broadcast, withdrawal, insertion)
What is a delusion of passivity?
The delusion that your actions are being controlled by an external agency
What are some positive symptoms of schizophrenia?
Delusions
Hallucinations
Thought disordered (derailment, snapping off)
Delusional perceptions
What are some negative symptoms of schizophrenia?
Catatonia Social withdrawal Blunting of affect Self neglect Anhedonia Negativism Poverty of speech
What are some cognitive symtoms of schozophrenia?
Abnormalities in attention
Memory defects
Abnormal executive cognitive function
How long do symptoms have to be present in order to diagnose schizophrenia?
1 month
What are some other causes of psychosis?
Paraphrenia
Delusional disorder
Drug induced psychosis
Schizoaffective disorder
In order to diagnose schizophrenia you need 1 of the following?
Delusions of thought control
Delusions of passivity
Auditory hallucinations
Blizzard delusions
OR in order to diagnose schizophrenia you need 2 of the following
Other hallucinations Thought disorganisation Catatonic symptoms Negative symptoms Change in personal behaviour
What is some exclusion criteria for diagnosing schizophrenia?
Mood disorder (schizoaffective) Drug taking (drug induced) Neurological conditions
What is the clinical out come without medications?
~20% show near full recovery
Some never recover
What is the clinical outcome with medication?
50% show near full recovery
What is the prevalence of schizophrenia?
5 per 1000 people
When is peak onset?
20-39
Male to female ratio
4:1
If one identical twin has schizophrenia what is the chance the other twin will have it?
53%
what fold increase in risk of developing schizophrenia to children of affected parents have?
15 times
what fold increase in risk of developing schizophrenia do siblings have compared to the general population?
10 times
What factors play a role in determining if someone has a predisposition to schizophrenia
Genetic factors
Environmental factors
Upbringing factors
What environmental factors may influence whether someone develops schizophrenia?
Low socioeconomic class (probably a consequence of disease)
Poor family relationships
Forceps delivery
Prenatal exposure to virus’s (higher incidence in those born in spring + after flu epidemic)
Someone might have a predisposition by may still no develop schizophrenia, why is this?
That have not been exposed to precipitating factors which induce a psychotic episode
What things may be a precipitating factor?
Stress Bereavement Leaving home Ending a relationship Substance misuse
What are the 4 aetiological theories of schizophrenia?
Structural brain abnormalities
Neurodevelopmental hypothesis
Neurodegenerative hypothesis
Neurotransmitter abnormalities
What are the structural abnormalities seen in SOME schizophrenic patients?
Enlarged ventricles
Decrease in brain volume (esp in the frontal and temporal lobe, hippocampus and amygdala)
What do patients with enlarged ventricles show?
More commonly show negative symptoms
In the structural brain abnormally hypothesis what is the significant of lack of glia?
No reactive gliosis thus cells do not degenerate but were not there in the first place
What is the neurodevelopmental hypothesis?
Abnormal neuronal selection and migration in foetal development which means the wrong cells survive and innervate the wrong places
In the neurodevelopmental hypothesis what causes symtoms to arise?
Normal restructuring of the synapses in adolescence is impaired
What suggests the schizophrenia is neurodegenerative?
Disease in progressive suggesting a decline in neurons. The disease in not static and response to medication decreases over time.
How might psychotic episodes support the neurodegenerative hypothesis?
An episode increases the amount of degeneration which makes subsequent episodes more likely.
Therefore early continuous treatment may minimum progression
What are the 3 neurotransmitters indicated in schizophrenia
Dopamine
Glutamate
5-hydroxytyptamine
Briefly, where does the neurotransmitter theory come from?
Studies of pharmacological agents
Phencyclidine is an NMDAR antagonists which causes hallucination and paranoia
Ampethamine increases dopamine release in the nucleus accumbens can causes positive (not not negative) symptoms
Within the mesocortical and mesolimbic what is thought to occur to dopamine levels?
Mesocortical there is too little dopamine = negative symptoms (?why antipsychotics make negative symptoms worse)
Mesolimbic there is too much dopamine = positive symptoms
What evidence supports the role of dopamine in schizophrenia?
Dopamine antagonists (D2) = treats positive symptoms Some evidences of increased dopamine function in schizophrenics Ampethamine gives you the postive symtoms of schizophrenia
What are the problems with the dopamine theory?
Ampethamine doe snot causes negative symptoms
Chance in dopamine function may be due to long term dopamine antagonistic therapy rather than disease itself
Evidence which supports a distinct dopamine pathway in schizophrenia?
Patients with Parkinson’s disease can have schizophrenia too
No correlation between ability of an antipsychotic to cause EPSPs and clinical efficacy
What does phencyclidine cause?
Both positive and negative symptoms
What occurs on genetic mutation which decreases NMDARs in mice?
They show schizophrenic behaviours e.g. Repeated movements, agitation and decreased social interest
What does postmortem analysis of schizophrenic patients show in terms of glutamate theory?
Increases cortical glutamate receptors
Increased binding of glutamate ligands in cortex, BG and hippocampus
However, reports show both an increase and decreases in glutamate binging in temporal lobe
Mechanism unclear!!!
What is the evidence the 5-HT is involved in schizophrenia?
5-HT mediated behaviours are disturbed e.g. Arousal, sleep, mood, perception)
Atypical antipsychotics show clinical beneficial side effect, some of which are antagonists to 5HT-2A receptors
LSD is a 5HT2A agonist and is psychogenic
Tryptophan worsens schizophrenia
SSRIs rarely causes psychosis
What is the problem with the %-HT theory of schozophrenia?
LSD = visual hallucinations not auditory and conceptional disorganisation and cognitive impairment are general absent
Where is the genetic predisposition hypothesised to effect? Why?
The frontal lobe
Relatives of schizophrenics who are not suffers show some impairment in the tests which assess frontal lobe function
?negative symptoms as frontal lobe to my shows similar symptoms
Where is the core deficit hypothesis to be?
Glutamatergic communication between the frontal and temporal lobe
Why is the the temporal lobe indicated in schizophrenia?
Temporal lobe epilepsy can manifest as + schizophrenic symptoms
