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 seem to treat.
Recently it has been discovered that Ketamine, a drug which acts on the receptors for different neurotransmitter, NDMA, can cause psychotic symptoms similar to schizophrenia in healthy adults, which only last as long as the drug is in their system.
The brains of patients with sz react differently to those of healthy people in some situations. Szs 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. Healthy volunteers who have been given ketamine, also show a similar response- their brainwaves do not change as much as a normal person’s when a tone is played that is not the same as the rest of the tones heard, for example.
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.