Described by Jamie Talan Scientists have described the first direct evidence that the brain chemical dopamine triggers the major symptoms of schizophrenia, including psychosis. The finding, published in the Proceedings of the National Academy of Science, is the result of a 30-year search for the chemical underpinnings of the devastating disease. Schizophrenia is caused by a very significant disruption of the dopamine system. Volkow has done similar studies with cocaine addicts and found that cocaine disrupts normal dopamine transmission.
Dopamine regulates movement and is also intimately involved with mood and motivation.
In the current study, Dr. Alan Breier and his colleagues at the National Institute of Mental Health used a PET, or Positron Emission Tomography, scan to study 11 schizophrenic patients, all with varying degrees of psychosis. Most had never been treated with anti-psychotic medications. The researchers measured the patients' behavioral responses while the PET scan enabled them to estimate the levels of dopamine released. Only in the schizophrenic patients were scientists able to find a relationship between behavior changes and the amount of dopamine released. Those with the most psychotic symptoms showed the highest activation of dopamine.