While numerous studies have shown that depression and dementia are related, none have proved causality. But a recent study published in the journal Neurology may have shed light on the link between the two disorders that disproportionately affect Black and Latino individuals.

Researchers from Chicago’s Rush University Medical Center and the University of Pennsylvania gathered data on 1,764 people 50 years or older, following them over an average period of eight years. In attempts to rule out a root problem that could cause both depression and dementia, the researchers initially pooled people who exhibited no cognitive problems.

At the end of the study, roughly half of the people had showed cognitive impairment, a sign of onset dementia, and 18 percent were diagnosed with dementia. When the data was analyzed, researchers found that those who previously showed symptoms of depression were more likely to develop cognitive impairment or dementia. In addition, the autopsies of the 600 people who died of various causes during the study showed that those who had at any point exhibited depressive symptoms were more likely to have in the brain amyloid plaques, signs of Alzheimer’s disease.

While there is no evidence that antidepressants treat dementia, the study showed that treating depression throughout life could prove a preventative strategy to reducing symptoms of dementia later in life.

The study further underlines the importance of addressing depression, an issue that often goes undiagnosed and untreated for many Black and Latino individuals. On average, of 11 Latinos with mental disorders, one will seek help from a mental health specialist and two will seek help from a general health provider, leaving the vast majority untreated, according to the National Alliance on Mental Illness. Even when Black or Latino individuals do seek help, they are less likely to be properly diagnosed.

Latinos are also 1.5 times more likely to develop Alzheimer’s Disease than white individuals, and non-whites are more likely to experience dementia, according to the Alzheimer’s Association. Some of the possible risk factors to the two, in addition to depression, are diabetes, high blood pressure and high cholesterol.