Israeli Study: Deep Brain Stimulation Shows Promise for Schizophrenia Treatment

In a potential breakthrough for individuals with treatment-resistant schizophrenia, Israeli scientists have developed a novel approach using deep brain stimulation (DBS). The research, published in Nature Communications, suggests that targeted electrical stimulation may restore cognitive functions impaired by the disorder, offering hope for a significant subset of patients who do not respond adequately to existing treatments.

Schizophrenia is a chronic and severe mental disorder that typically emerges in early adulthood and often persists throughout a person’s life. Affecting approximately 21 million people worldwide, according to the World Health Organization, roughly one-third of those diagnosed are considered treatment-resistant, presenting a substantial clinical challenge. Symptoms can include hallucinations, delusions, disorganized thinking, and significant social withdrawal, leading to substantial functional and occupational impairments.

Dr. Nir Asch, a researcher at Rambam Health Care Campus in Haifa, Israel, led the study. He explained that the research moves beyond simply addressing symptoms to understanding the underlying neurological mechanisms of the illness. “A problem we have with many psychiatric diseases is that we define them by the symptoms,” Dr. Asch told The Times of Israel. “In our paper, we provide a clear theory about what is happening on a mechanical level in the brain, and also a way to solve it.”

The study’s foundation lies in understanding how the brain processes information and makes predictions. Dr. Asch described the brain as a “prediction machine,” constantly building models of the world based on sensory input. In schizophrenia, this predictive process becomes disrupted, leading to “cognitive inflexibility” – a difficulty in adapting to changing circumstances and a tendency to remain fixated on internal models even when they are inaccurate.

The research team focused on a specific brain region called the globus pallidus externus (GPe), part of the basal ganglia–dorsolateral prefrontal cortex (BG–DLPFC) network. This network is crucial for decision-making, habit control, and adapting to new situations. The GPe acts as a “dynamic valve” regulating communication within the network. Disruption in this communication contributes to the confused thinking characteristic of schizophrenia.

To investigate this, the scientists conducted experiments on two female African green monkeys. They induced a psychotic state in the monkeys using phencyclidine (PCP), a drug known to cause hallucinations and dissociations, mimicking some of the symptoms of schizophrenia. They observed a significant reduction in cognitive flexibility and an increase in chaotic behavior.

Applying low-frequency DBS (13 Hz) to the GPe yielded remarkable results. “The cognitive inflexibility was cured,” Dr. Asch reported. “The monkeys returned to the levels of when they were healthy, and they were also much less chaotic.” This suggests that modulating activity in the GPe can restore the brain’s ability to adapt and process information effectively.

The approach builds upon the pioneering work of Prof. Hagai Bergman of the Hebrew University of Jerusalem, a leading figure in DBS research, initially developed for Parkinson’s disease. Prof. Bergman’s earlier discoveries demonstrated the potential of stimulating specific brain areas to alleviate neurological symptoms, paving the way for exploring DBS as a treatment for psychiatric disorders.

Dr. Idit Tamir, director of the functional neurosurgery unit at Rabin Medical Center, who was not involved in the study, noted that improvements in cognitive flexibility with DBS to the basal ganglia are already observed in patients with Parkinson’s and obsessive-compulsive disorder. She emphasized the importance of cognitive flexibility in everyday life, highlighting its role in “hundreds of decision-making moments” we experience daily.

While the findings are promising, it’s important to note that this research was conducted on animals. The next step is a clinical trial in humans to determine the safety and efficacy of this DBS approach for individuals with schizophrenia. Dr. Asch and his team are already planning these trials, motivated by the potential to offer a new treatment option for a population with limited alternatives.

The potential impact of this research extends beyond the scientific realm. Dr. Asch, having transitioned from full-time research to treating patients, emphasized the profound impact of the illness on individuals and their families. “It can be very frustrating as a doctor when we don’t have great treatments,” he said. “If we can add more tools that are effective and pave the way to recovery, then it would be so wonderful.”

People with schizophrenia also face a significantly reduced life expectancy, dying on average nine years earlier than the general population, often due to physical health conditions like diabetes. Addressing the complex interplay between mental and physical health remains a critical aspect of comprehensive care for individuals with schizophrenia.