Schizophrenia (Yvonne Mbaki) Flashcards
Men are more susceptible to schizophrenia than women, what is one theory as to why?
Oestrogen has a regulatory role in dopamine receptor sensitivity
When does schizophrenia typically present?
In late adolescence or early adulthood, (acute onset over 2-3 weeks)
What are some of the environmental factors that can increase the risk of development?
Urban areas, men are more prone
Countries further from the equator with a colder climate, more common cases
Perinatal complications; severe malnutrition, exposure to stressful events, birth complications, altered brain development in early life predisposes people to schizophrenia in later life
Early cannabis use (other drugs?)
Advancing parental age (germ cell mutations increase risk of schizophrenia development in the child.)
Is the risk of schizophrenia genetic?
Yes, increased risk in people with a family history
Amplification of risks in twin studies confirms this genetic contribution
Neuregulin and Dysbindin play a role in development and so are susceptibility genes as they influence neurodevelopment and synaptic function.
What are positive and negative symptoms in schizophrenia?
Acute positive, chronic negative
What is an example of positive symptoms?
Characteristic symptoms: thought insertion, 3rd person auditory hallucinations
Symptoms persistent for > 1 month
Exclusion of organic disease or a mood disorder such as bipolar already established
What is an example of negative symptoms?
Characteristic symptoms: flattened mood, indifference and loss of drive, social isolation, poor self-care, poverty of speech
What are other symptoms of schizophrenia not designated to positive and negative?
Cognitive impairment; affecting attention, working and semantic memory.
What is working memory?
Temporary storage and manipulation of information, needed for learning, reasoning and language comprehension
What is semantic memory?
Long term memory that processes ideas and concepts, inclusive of common knowledge such as colours, sounds of letters etc
What are sub syndromes in schizophrenia?
Paranoid schizophrenia - auditory delusions and hallucinations
Disorganised schizophrenia - thought disorder, odd behaviour, inappropriate mood
Catatonic schizophrenia - rare form due to the treatment of condition (taking anti-psychotics), symptoms include not being able to move or speak, person stares, holds body in a rigid position, unaware of surroundings
How is schizophrenia diagnosed?
Patients must have one or more of the following: 1. delusions 2. hallucinations Two of the following 1. delusions 2. hallucinations 3. disorganised speech 4. catatonic behaviour 5. negative symptoms i.e. flattened mood, inability to speak, general lack of drive
What is the dopamine theory behind the cause of schizophrenia?
Excess dopamine
Excess dopamine receptors
What is the evidence for the dopamine theory of schizophrenia?
Antipsychotic drugs = D2 receptors antagonists
Dopamine agonists such as amphetamines, levodopa = paranoid psychosis
CSF and brain studies from patients = abnormal levels of dopamine, its metabolites, enzymes or receptors.
Is dopamine excess the sole contributor to schizophrenia?
No, there is evidence that dopamine changes glutamate transmission downstream, signalling via the NMDA receptor is implicated.
NMDA antagonists ketamine and phenycylidine (PCP) prodce schizophrenia-like syndromes.
Other theories;
Abnormalities in cerebral blood flow and metabolism (impairment of neuronal circuits)
Specific impairment in frontal cortex, hippocampus, thalamus and cerebellum
In schizophrenic patients there are structural brain changes. What are these?
Enlargement of the lateral ventricles, slight decrease in the size of the brain, altered neuronal and synaptic organisation, affected white matter and no gliosis (no glial cell damage).
Neurodevelopmental (not neurodegenerative).
What kind of management strategy is employed for schizophrenia?
Depending on the stage of the illness;
Intervention includes physical, psychological and social.
Initial assessment requires compulsory admission, drug free if possible. Medication such as benzodiazepines may be needed to calm an acutely psychotic patient.
Aside from the management strategy, how are symptoms and treatment managed?
Antipsychotic medication effective against positive symptoms with gradual onset of therapeutic effect (2-3 weeks).
Investigate the context of positive symptoms i.e. drug misuse that may contravene treatment i.e. cannabis.
Family support is key, early intervention, CBT.
Similar treatment for chronic schizophrenia with regular monitoring.
What is the mechanism of action for pharmacological treatment?
Inhibit D2 receptors
Reverse excess dopamine activity in mesolimbic system (site for psychosis symptoms)
When treating a single schizophrenic episode how should treatment be carried out?
Maintained for 12-24 months after the episode
If improvement is noted then tail off medication because tardive dyskinesia is just one of many side effects
What is Tardive Dyskinesia?
Tardive dyskinesia (TD) is a medical term that describes the involuntary sudden, jerky or slow twisting movements of the face and/or body. Parkinsonian like side effect
