Psychosis and schizophrenia Flashcards
When does onset of schizophrenia typically occur?
Early adulthood
What is the prevalence of schizophrenia?
1.2%
What percent of schizophrenia patients will typically die by suicide?
10%
What are possible causes for schizophrenia?
Inherited risk factor
Environment
Epigenetics
What are positive symptoms of schizophrenia?
Hallucinations Delusions Paranoia Inappropriate emotions Persecution complexes
What are negative symptoms of schizophrenia?
Apathy
Depression
Social incompetence
What are cognitive symptoms of schizophrenia?
Attentional defects
Memory loss
Executive dysfunction
Describe the hyperactive dopaminergic theory of schizophrenia and its support
Increased dopamine transmission
D2 receptor agonists and dopamine in animals causes schizophrenic behaviour
There is a strong correlation between antipsychotic potency and D2 receptor blocking effects
What doubts the hyperactive dopaminergic theory of schizophrenia?
There is no support for the theory in post-mortems or PET studies
No evidence to see if D2 receptors are abnormal in untreated schizophrenia
Unknown genetic aetiology
Describe the hypoactive glutamatergic theory of schizophrenia and its support
Reduced glutamate in pyramidal cells
Allelic variants of Glu receptors are well documented and implicated in schizophrenia
Glutamate receptor antagonism causes positive and negative symptoms
What evidence suggests serotonin is implicated in schizophrenia?
5-HT receptor antagonists are effective antipsychotics
Describe the mechanism of typical antipsychotics
Selective D2 or D3 antagonism
Which symptoms do typical antipsychotics treat?
Positive
Give an example of a typical antipsychotic?
Chlorpromazine, haloperidol, thioridazine, flupenthixol
Describe the mechanism of atypical antipsychotics
Selective D2 or D3 antagonism with added affinities depending on the drug
Give an example of an atypical antipsychotic
Sulpiride, pimozide, remoxipride or clozapine
What is the added affinity for clozapine and why is it the ‘gold-standard’ antipsychotic
It is a D4 receptor antagonist
Treats negative symptoms as well as positive
What gives rise to the delayed therapeutic effect of antipsychotics?
Synthesis and expression of dopamine and its receptors increases to counteract the initial decrease
Initial increased firing of mesolimbic and nigrostriatal pathways
What are side effects of anti-psychotics?
Sedation, apathy and indifference
Why is it difficult to treat a patient using antipsychotics
Difficult to determine dosage
Individual response to different drugs
Low compliance
Describe extrapyramidal syndrome and its treatment
Dopamine antagonism causes Parkinson-like syndromes
Reversed by stopping treatment or co-treatment with atropinic drugs
Describe tardive dyskinesia
Choreic symptoms that develop after long-term antipsychotic use
Describe the endocrine effects arises from taking antipsychotics
Dopamine inhibits prolactin production
Prolactin causes galactorrhoea, infertility and gynaecomastia
What other side effects are common with antipsychotics?
Muscarinic blockade, adrenoreceptor blockade, hypothermia, weight gain, jaundice and leucopenia
Why are atypical antipsychotics preferred, despite a lower therapeutic effect?
They have fewer side effects
