Scientists at Imperial College London have come up with new brain chemical findings that could open the door to new schizophrenia drugs.
The research by the doctors has linked psychosis with an abnormal relationship between two signalling chemicals in the brain, instead of concentrating on the one. The findings could result in a new approach to preventing psychotic symptoms, which could lead to better drugs for schizophrenia.
According to Dr James Stone, traditional treatments and research of schizophrenia has linked the illness with abnormally high levels of a neurotransmitter called dopamine in a region of the brain called the striatum. He told TechEye the drugs currently used to treat schizophrenia block the effects of dopamine in the brain.
However, these drugs are not effective for all patients, and can have serious side effects.
“The new research has moved on the idea that it is just dopamine that affects people and is the cause of schizophrenia,” he told us.
“We can now see that symptoms occur as a consequence of changes in another brain chemical, glutamate. Glutamate-releasing cells in a brain region called the hippocampus connect to the striatum and influence the activity of dopamine-releasing cells. Drugs that interfere with glutamate signals in the brain might therefore be able to prevent psychotic symptoms in people with schizophrenia,” he added.
Schizophrenia is one of the most common severe mental health conditions. Sufferers experience symptoms of psychosis – an inability to distinguish between reality and imagination – such as hallucinations and delusions. The condition tends to begin in the late teens or twenties, and usually persists for the rest of the sufferer’s life.
The researchers carried out brain scans on 16 people with an at-risk mental state for psychosis and 12 healthy volunteers, to measure the levels of glutamate and dopamine. In people with early signs of psychotic symptoms, there was a negative correlation between glutamate levels in the hippocampus and dopamine levels in the striatum area. There was a particularly marked
correlation in the subjects who went on to develop psychosis later. There was no correlation in the healthy subjects.
“In healthy volunteers, there’s no clear relationship between glutamate and dopamine, but in people with early signs of psychosis, we see this abnormal relationship,” Dr Stone told us.
“This suggests that the signalling pathway between the hippocampus and the striatum is dysfunctional, and we might be able to treat this by targeting the glutamate system. If drugs that act on glutamate signalling can prevent psychotic symptoms, it would mean a real shift in the way that people are treated for schizophrenia.”
Dr Stone told us that there were going to be more trails into this research. However, he said drugs companies were already looking at medicines that could help in light of the new findings. These could be available within the next few years.