Researchers have identified a potential new target for treating delusions in patients with schizophrenia-spectrum disorders by linking symptom severity to how the brain perceives environmental unpredictability.
A study published in the journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging suggests that volatility priors, which represent mental expectations regarding how much an environment will change, are modifiable. This finding indicates that as delusions subside, the brain’s predictive settings may stabilize, offering a possible avenue for new therapeutic interventions.
Delusions are common in psychotic disorders and are characterized by strong beliefs that persist despite evidence to the contrary. In individuals with schizophrenia-spectrum disorders, the brain often sets volatility priors to an abnormally high level, causing the environment to seem chaotic and unstable. This perceived instability can drive the brain to generate delusions to make sense of the perceived chaos.
The study, led by Julia M. Sheffield of Vanderbilt University Medical Center, followed 75 adults recovering from acute psychotic episodes over a six-month period. Researchers assessed their cognitive processes through a probabilistic reversal learning task and compared the results to a control group of 71 individuals.
The data showed that participants with schizophrenia-spectrum disorders had significantly higher volatility priors than the control group. While these levels remained elevated over the study period, they were longitudinally associated with the severity of delusions and paranoia. Notably, these associations were not linked to symptoms of depression or worry, and the results remained consistent even after controlling for cognitive ability and the use of antipsychotic medications.
Researchers addressed potential practice effects, where participants might improve simply by repeating a task, noting that the elevated volatility priors were still evident at the sixth month of the study. This suggests the findings are a reflection of the participants’ cognitive states rather than mere task familiarity.
The research, which was supported by a grant from the National Institute of Mental Health, suggests that most current treatments for delusions involve antipsychotic medications that target the dopamine system. These new findings indicate that adjusting how a patient expects their environment to behave could serve as a novel treatment target. This may lead to the development of psychological interventions, such as specialized cognitive behavioral therapy, to help patients manage and recover from debilitating symptoms.
