Psychosis Flashcards
(21 cards)
What are positive symptoms in schizophrenia?
Hallucinations and delusions.
What are negative symptoms of schizophrenia?
Loss of motivation/memory and social withdrawal.
What is schizophrenia caused by?
Genetic interactions and environmental influences.
What three physiological effects do people with schizophrenia experience?
- Excessive production of dopamine.
- Hypo function of NMDA receptors
- Reduction of GABA signalling.
What are the names of the three theories of schizophrenia?
1 Dopamine hypothesis.
- Glutamate hypothesis.
- Serotonin hypothesis.
Explain the dopamine hypothesis of schizophrenia. What receptors are involved?
Schizophrenic symptoms are due to hyperactivity of the dopamine system. Dopamine receptors D1 and D2.
What kind of receptors are D1 and D2? Where are they distributed?
D1: stimulators GPCR
D2: inhibitory GPCR
Present in the nigrostriatal and tuberoinfundibular systems and meso cortical system.
What is the function of Mesocortical/Mesolimbic system?
Mediate learning, memory, and thought processing.
What is the function of the nigrostriatal system?
Involved in movement initiation.
What is the function of the tuberoinfundibular system?
Controls hormone release (Prolactin)
Explain the glutamate hypothesis. What receptors are involved?
Inhibition/deficiencies in NMDA receptors and glutamate signalling, leads to iver activation of glutamate neurotransmitters.
Explain the serotonin hypothesis. What receptors are involved?
Symptoms are due to increased serotonin signalling; over activation of 5HT-2A receptors in prefrontal cortex.
What are first generation anti-psychotics? What are two examples?
Target both D1 and D2 receptors. Haloperidol and chlorpromazine.
What are second generation anti-psychotics? What are examples?
Antagonists at 5HT and D2 receptors. Have looser binding so less adverse effects. Examples are clozapine and risperidone.
What are extrapyramidal symptoms? What are they caused by?
Parkinson-like syndromes due to decreased dopamine activity (because of high D2 inhibition) in the nigrostriatal system.
What is hyperprolactinemia? What is it caused by?
High prolactin concentration in the blood caused by excessive dopaminergic receptor inhibition.
What is the mesolimbic and nigrostriatal kinetic hypothesis for side effects?
Dopamine is released in synapse between cells and binds to receptors (localized).
What is the tuberoinfundibular kinetic hypothesis for side effects?
Dopamine is secreted into the bloodstream and carried across the blood-brain barrier.
What is the binding mechanism of haloperidol? What symptoms does this cause?
Fast on, slow off mechanism. Causes high D2 receptor affinity in the striatum and pituitary; kinetic dysfunction and hyperprolactinemia.
What is the binding mechanism of Chlopromazine? What symptoms does this cause?
Fast on, fast off mechanism. High affinity for D2 receptors in the striatum, causing kinetic dysfunction. Fast-off means low affinity for pituitary receptors therefore prolactin concentration is not impacted.
What is the binding mechanism of Clozapine? What symptoms does this cause?
Slow on, fast off. No adverse effects. However, there is a high affinity for D4 receptors on granulocytes, causing loss of WBC.
