Genes responsible for regulating neurotransmitters in the brain could be to blame for depression in females, according to a new study by researchers at the University of Illinois at Chicago (UIC).

The research team, headed by Monsheel Sodhi, an assistant professor of pharmacy practice at UIC, studied the postmortem tissue of psychiatric patients to collect their data. Sodhi noticed that many female patients who had depression also had strangely high levels of genes that regulate the glutamate system, which helps the brain process information.

Glutamate is the major excitatory neurotransmitter in the brain, and it plays an important role in epilepsy, autism, schizophrenia, and Alzheimer’s disease — all of which are conditions associated with an abnormal glutamate system.

Sodhi and her colleagues analyzed the tissue from those who had suffered from depression, many of whom had died by suicide, she said in a press release. The team discovered that females with depression had the highest levels of several glutamate receptor genes, which they theorized might have made the patients more prone to depression.

Gender does matter when it comes to depression and suicide — females are two to three times more likely to attempt suicide than men, but men are four times more likely to die, the Centers for Disease Control and Prevention (CDC) reported. The CDC added over 41,000 people die by suicide each year in the United States, and that number is going up — it is currently the second-leading cause of death in people aged 15 to 34 years. What's more is over 90 percent of the people who take their lives suffer from a mental illness, with depression being the most prominently represented.

Sodhi and her coworkers were interested in recent studies that found that a low dose of ketamine, which affects the glutamate system's activity, can quickly eliminate depression in two-thirds of patients not responding to orthodox treatments. These traditional treatments target the monoamine system, which secretes the neurotransmitters dopamine, serotonin, and norepinephrine.

“Our data indicates that females with major depression who are at high risk of suicide may have the greatest antidepressant benefit from drugs that act on the glutamate system, such as ketamine,” Sodhi said. The study suggests new treatments target glutamate receptors along with biochemical markers that may be able to assess suicide risk.

Currently, only one third of patients receiving treatments achieve significant remission of their depression — even than, this process can take weeks or longer. For patients with a high risk of suicide, this lack of timely treatment could be very dangerous.

Source: Gray A, Hyde M, Deep-Soboslay A, Kleinman J, Sodhi M. Sex differences in glutamate receptor gene expression in major depression and suicide. Molecular Psychiatry. 2015.