Psychosis

Question 1

What are positive symptoms in schizophrenia?

Answer 1

Hallucinations and delusions.

Question 2

What are negative symptoms of schizophrenia?

Answer 2

Loss of motivation/memory and social withdrawal.

Question 3

What is schizophrenia caused by?

Answer 3

Genetic interactions and environmental influences.

Question 4

What three physiological effects do people with schizophrenia experience?

Answer 4

1. Excessive production of dopamine.
2. Hypo function of NMDA receptors
3. Reduction of GABA signalling.

Question 5

What are the names of the three theories of schizophrenia?

Answer 5

1 Dopamine hypothesis.

2. Glutamate hypothesis.
3. Serotonin hypothesis.

Question 6

Explain the dopamine hypothesis of schizophrenia. What receptors are involved?

Answer 6

Schizophrenic symptoms are due to hyperactivity of the dopamine system. Dopamine receptors D1 and D2.

Question 7

What kind of receptors are D1 and D2? Where are they distributed?

Answer 7

D1: stimulators GPCR
D2: inhibitory GPCR
Present in the nigrostriatal and tuberoinfundibular systems and meso cortical system.

Question 8

What is the function of Mesocortical/Mesolimbic system?

Answer 8

Mediate learning, memory, and thought processing.

Question 9

What is the function of the nigrostriatal system?

Answer 9

Involved in movement initiation.

Question 10

What is the function of the tuberoinfundibular system?

Answer 10

Controls hormone release (Prolactin)

Question 11

Explain the glutamate hypothesis. What receptors are involved?

Answer 11

Inhibition/deficiencies in NMDA receptors and glutamate signalling, leads to iver activation of glutamate neurotransmitters.

Question 12

Explain the serotonin hypothesis. What receptors are involved?

Answer 12

Symptoms are due to increased serotonin signalling; over activation of 5HT-2A receptors in prefrontal cortex.

Question 13

What are first generation anti-psychotics? What are two examples?

Answer 13

Target both D1 and D2 receptors. Haloperidol and chlorpromazine.

Question 14

What are second generation anti-psychotics? What are examples?

Answer 14

Antagonists at 5HT and D2 receptors. Have looser binding so less adverse effects. Examples are clozapine and risperidone.

Question 15

What are extrapyramidal symptoms? What are they caused by?

Answer 15

Parkinson-like syndromes due to decreased dopamine activity (because of high D2 inhibition) in the nigrostriatal system.

Question 16

What is hyperprolactinemia? What is it caused by?

Answer 16

High prolactin concentration in the blood caused by excessive dopaminergic receptor inhibition.

Question 17

What is the mesolimbic and nigrostriatal kinetic hypothesis for side effects?

Answer 17

Dopamine is released in synapse between cells and binds to receptors (localized).

Question 18

What is the tuberoinfundibular kinetic hypothesis for side effects?

Answer 18

Dopamine is secreted into the bloodstream and carried across the blood-brain barrier.

Question 19

What is the binding mechanism of haloperidol? What symptoms does this cause?

Answer 19

Fast on, slow off mechanism. Causes high D2 receptor affinity in the striatum and pituitary; kinetic dysfunction and hyperprolactinemia.

Question 20

What is the binding mechanism of Chlopromazine? What symptoms does this cause?

Answer 20

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.

Question 21

What is the binding mechanism of Clozapine? What symptoms does this cause?

Answer 21

Slow on, fast off. No adverse effects. However, there is a high affinity for D4 receptors on granulocytes, causing loss of WBC.