Some 21 million people worldwide suffer from the debilitating and devastating mental health disorder of schizophrenia. The symptoms not only include the well-known hallucinations and delusions but also a disruption of normal functions resulting in disordered speech, disorganized behavior, inability to perform daily tasks, lack of emotional expression and lack of motivation, among others.

The side effects of medications are sometimes so intolerable that patients stop taking them. In other cases, the symptoms are resistant to medication.

Enter Nir Asch, a doctor and researcher in the psychiatric department at Rambam Health Care Campus in Haifa, who said that the problem with current treatments lies in treating the symptoms instead of fixing the problem in the brain.

“A problem we have with many psychiatric diseases is that we define them by the symptoms,” he said in an interview. “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.”

Hagai Bergman, a neuroscientist from the Hebrew University of Jerusalem, provided guidance for the study. The professor pioneered a treatment called deep brain stimulation (DBS) that has reduced symptoms in patients suffering from Parkinson’s disease, another brain disorder. The study showed that DBS is also effective in treating schizophrenia.

Two African green monkeys were given phencyclidine, a drug that simulates the symptoms of schizophrenia. When the researchers applied deep brain stimulation, they observed immediate results.

In the brain, the basal ganglia and the dorsolateral prefrontal cortex form a network called the BG–DLPFC network that helps us make decisions and adapt to situations as they change. The globus pallidus externus (GPe) acts like a filter that controls the information flow between the parts of the network. When this is disrupted, a person gets stuck in confused thinking and is unable to process changes around him, leading to delusions and hallucinations. DBS focuses on the GPe, restoring function.

“The cognitive inflexibility was cured,” Asch said about the experiment. “The monkeys returned to the levels of when they were healthy, and they were also much less chaotic.”

“Because the study was successfully performed on non-human primates, whose brains are remarkably similar to those of humans, we’re already meeting to discuss the best way to move forward,” he added, noting that they were ready for clinical trials in humans.

Asch said that working with patients and their families gives him the motivation to press forward.

“When I did the research, I was very much interested in understanding the science,” he said. “But now, seeing the patients and witnessing the burden on their families gives me a lot of motivation to take it to the next step.”

“It can be very frustrating as a doctor when we don’t have great treatments,” he added. “If we can add more tools that are effective and pave the way to recovery, then it would be so wonderful.”