A new study finds clues as to psychosis susceptibility in the folds of the cortex.
Characterized by hallucinations and delusions, psychosis is a hard condition to understand, treat, and, importantly, predict.
People who present with psychotic symptoms do not necessarily go on to develop acute psychosis.
However, it is difficult to predict whose symptoms will continue and worsen.
People can and do recover from acute psychosis, but timing is key. The earlier treatment starts, the better the outcome is likely to be. For this reason, finding a way to catch those at highest risk of developing acute psychosis is vital.
Psychosis and the brain
Earlier work has established that psychosis is, at least in part, due to faulty communication between parts of the brain. Modern imaging has made it possible to visualize these broken pathways.
But, despite improvements in understanding, a method to distinguish individuals whose condition will escalate to acute psychosis has remained elusive.
Other studies have looked for changes in the volume of regional gray matter in the brain. Although changes in people with psychosis have been measured, it seems that they can occur prior to psychosis beginning, during onset, or after psychosis has begun. This makes its power of prediction relatively weak.
Recently, researchers from the University of Basel in Switzerland revisited this problem. Led by Drs. André Schmidt and Lena Palaniyappan, the team focused on the gross anatomy of the brain. In particular, they were interested in the folds on the surface of the brain, or the cortex.
The development of these convoluted lumps and bumps on the cortex is known as gyrification. The folds are called gyri, and the troughs in-between are referred to as sulci. The process of gyrification is completed within the first 2 years of life and, from then on, the structures remain relatively consistent.
Studies have found that errors in gyrification can lead to conditions such as schizophrenia.
The researchers focused their investigation on the interaction between the gyri; they were on the hunt for any measurable impairments or changes in communication in high-risk individuals.
The team hoped to find enough differences in cortical communication to make the early diagnosis of psychosis a possibility.
For the study, they assessed the brains of over 160 participants. These were 44 healthy controls, 38 people who had experienced their first psychotic episode, and 79 people who were at high risk of developing acute psychosis. Of the 79 high-risk participants, 16 went on to develop acute psychosis.
Investigating gyri communication
They "reconstructed" the nerve pathways of each brain using MRI scans and techniques taken from mathematical graph theory, which is a useful way to determine how many points within a system interact (referred to as nodes).
They found that, when compared with healthy brains, those with an initial psychotic episode were different. And, when the first episode brains were compared with the individuals who developed acute psychosis, there was a reduction in integration and increased segregation between gyri. Their findings were published earlier this week.
Using the results, they were able to predict who would transition from first episode to acute psychosis in more than 80 percent of cases.
The authors conclude:
"These findings suggest that there is poor integration in the coordinated development of cortical folding in patients who develop psychosis."
Dr. Schmidt says, "Our results indicate that this type of network analysis could significantly improve individual risk prognoses."
However, the study authors also note that this was a relatively small study and much more work will be needed.
Dr. Schmidt concludes, "Future longitudinal studies with larger samples are now needed to validate the prognostic accuracy of this measurement."