New model for Schizophrenia

A way to model in a monkey the brain responses seen in patients with schizophrenia has been described by US researchers...

Schizophrenia is a serious, debilitating mental illness, but is poorly understood. Most treatments work on the basis that it is cause by a dysfunction in a particular neurotransmitter system in the brain: dopamine. However, although treatments are often effective for the 'positive' symptoms - delusions and hallucinations - there are other symptoms, such as problems with decision making and other cognitive processes that the drugs do not control.

The brains of patients with schizophrenia react differently to those of healthy people in some situations. Schizophrenics are less able to detect a stimulus that is different to the rest, and direct their attention to it- something most of us do very naturally. This difference can be seen using electroencephalography, or EEG, where electrodes are placed on the scalp to read the brain waves.

Intriguingly, the drug ketamine, an anaesthetic agent that acts on NMDA receptors that respond to the neurotransmitter glutamate, can also cause psychotic symptoms similar to schizophrenia in healthy adults; critically, these psychotic symptoms last only as long as the drug is in a person's system.

Now, in a study published in PNAS, Gil-da-Costa and colleagues from the Salk Institute for Biological Studies have shown that macaque monkeys show the same difference in brain activity when given ketamine. The hope is that this could lead to a new wave of treatments, which counteract this change in NDMA receptor activity, rather than affecting the dopamine circuits.