Pharmacology of Psychoses

Question 1

Explain the dopamine theory of schizophrenia and its limitations.

Answer 1

The dopamine theory of schizophrenia states that the abnormality in brain function in schizophrenia is due to overactivity in brain dopaminergic pathways, especially the mesolimbic pathway. Drugs that block dopamine (D2) receptors are affective in treating schizophrenia and drugs that increase dopaminergic activity aggravate schizophrenia. Schizophrenics have decreased D2 receptors in their prefrontal lobes, but an increased D2 receptor density in the striatum. Limitations to this theory suggest that there are other neurotransmitters or pathways involved in schizophrenic symptoms. Evidence supporting this includes:

• The observation that blockade of D2 receptors does not immediately reduce symptoms, suggesting there is something else going on to produce antipsychotic effects.
• The fact that weak D2 blockers are still effective in treating schizophrenia
• Evidence that serotonin and glutamate also play a role in symptom evolution
• Antipsychotic agents that block D2 receptors are only minimally effective overall

Question 2

Describe the mechanism of antipsychotic drug action, including a description of brain dopamine systems affected

Answer 2

x

Question 3

Discuss the potential role of abnormalities in glutamate neuronal systems in the symptomatology of psychoses.

Answer 3

x

Question 4

Describe the relationship between receptor blocking potency and selectivity (esp. 5HT vs DA) to efficacy in schizophrenia and side effect profile for typical and atypical antipsychotic agents.

Answer 4

x

Question 5

Chlorpromazine

Answer 5

x

Question 6

Haloperidol

Answer 6

x

Question 7

Clozapine

Answer 7

x

Question 8

Risperidone

Answer 8

x

Question 9

Olanzapine

Answer 9

xx

Question 10

Aripiprazol

Answer 10

x