The same process that turns metal into rust is happening in the brains of people with schizophrenia, researchers have reported.

Findings presented at the American College of Neuropsychopharmacology’s annual meeting suggest these patients have higher levels of “oxidative stress” than healthy brains or even people with another mental illness, bipolar disorder. According to a statement from the ACNP, neuroscientists used an MRI to peek into schizophrenia patients’ brains and believe the chemical imbalance could be contributing to their condition.

Read: Why Schizophrenics Hallucinate

Oxidative stress occurs when certain highly reactive atoms or molecules damage cells. Antioxidants in the body are supposed to neutralize these damaging agents, called “free radicals,” but when they don’t and the radicals accumulate, it can lead to oxidative stress. In the worst cases, oxidative stress could damage DNA, the Mayo Clinic says, and has been implicated in serious medical conditions like cancer, heart disease, diabetes, Alzheimer’s and Parkinson’s.

Metal corrodes into rust in a similar process of excessive oxidation.

The statement from the American College of Neuropsychopharmacology said many experts suspect excessive oxidation plays a role in schizophrenia, as it may “cause inflammation and cellular damage. However, measuring this process in the living human brain has remained challenging.”

But does the schizophrenia come first or the oxidative stress? The study’s lead investigator and psychiatry professor at Harvard Medical School, Dr. Fei Du, said in the statement that “intensive energy demands on brain cells leads to accumulation of highly reactive oxygen species,” like those free radicals that damage cells.

In the schizophrenic brains he observed, Du found a 53 percent elevation of a certain molecule that is used to measure oxidative stress, and a similar level in people in the early stages of the mental illness, suggesting it is an issue from the start. Although bipolar disorder has some similarities to schizophrenia and bipolar brains also had elevated levels of the molecule studied, those levels did not reach as high as they did in people with schizophrenia.

“We hope this work will lead to new strategies to protect the brain from oxidative stress and improve brain function in schizophrenia,” Du said.

Read: Sunshine Could Be Therapy for Schizophrenia

Read: 4 Medical Illnesses Mistaken For Witchcraft