New clues reveal risk of psychotic illness
People with psychotic illness show similar brain changes to immediate family members without any signs of illness, according to a new study published today in the journal JAMA Psychiatry.
Researchers found that these brain changes represent a marker of genetic risk of developing psychotic illnesses, such as schizophrenia.
The lead researcher says these genetic markers could be targeted in the development of new treatments that may help to reduce the risk of developing psychotic illness.
"First-degree relatives of people with psychosis are at increased genetic risk of developing a psychotic illness," said lead researcher, Associate Professor Alex Fornito, Deputy Director of Monash Clinical and Imaging Neuroscience in the School of Psychology and Psychiatry.
"We have found that people with psychosis and their unaffected first-degree relatives, who otherwise present no signs of illness, show similar brain changes when compared to healthy people," he added.
Even at the earliest signs of illness, Fornito said patients showed altered activity (when compared to healthy people) in a specific brain circuit that links the striatum (a region deep in the brain) with the prefrontal cortex, and plays an important role in attention, learning and memory.
"The fact that we see the same brain changes in this group, in the absence of any overt signs of illness, points to a neural biomarker of risk for psychosis," noted Fornito.
"Patients who showed more severe changes in this circuit also showed more severe psychotic symptoms, providing a direct link between these brain changes and illness severity," he explained.
The study examined 19 young people experiencing their first episode of psychotic illness, as well as 25 of their parents or siblings who presented no signs of illness. Another 26 healthy and unrelated participants were also recruited as a comparison group.
Using magnetic resonance imaging, or MRI, to map the activity of different brain systems, the research team found a change in brain activity that was specific to patients with psychotic illness, but not their healthy relatives.
Fornito said this change may reflect a 'switch' that determines whether a person transitions from an at-risk state to full-blown illness.
"We know that activity in brain circuits linking the striatum and prefrontal cortex are heavily influenced by the neurotransmitter dopamine, which is a major target for all medications currently used to treat psychosis," Fornito explained.