What is the Dopamine Hypothesis in schizophrenia?
The dopamine hypothesis initially stated that in people with schizophrenia, certain regions of the brain contain excess dopamine, thereby causing symptoms of the disease, particularly positive symptoms. The dopamine hypothesis arose from, and has since been supported by, several observations : • Most antipsychotic drugs that are effective in treating the positive symptoms of schizophrenia block dopamine D2 receptors. • Drugs that increase dopamine levels in the brain, including amphetamines and cocaine, mimic the positive symptoms of schizophrenia. A higher density of D2 receptors has been found postmortem in the frontal cortex of people with schizophrenia. It is not clear, however, whether the increased dopaminergic activity is due to too much dopamine, too many dopamine receptors, excessive dopamine receptor sensitivity, or a combination of all three factors. In recent years, refinements of the dopamine hypothesis have suggested that certain symptoms of schizophrenia and some side ef
