A new study by the Institute for Health Metrics and Evaluation (IHME) has made a shocking discovery: over 2,000 counties in the U.S. suffered from 200 percent increase in deaths linked to substance abuse -- including alcohol and drugs -- and mental health problems since 1980.

Kentucky, West Virginia, and Ohio, the study says, had the worst: having an alarming rate of surges in death, by over 1,000 percent, Eureka Alert reports.

The study, entitled "US County-Level Trends in Mortality Rates for Major Causes of Death, 1980-2014" published in the journal JAMA, looked closely at how mortality rates in the U.S. has changed over the years. Researchers examined deaths in 21 cause groups -- from chronic illnesses (diabetes and other endocrine diseases), to infectious diseases (HIV/AIDS and tuberculosis), to accidents including traffic fatalities.

Cardiovascular disease emerged as the leading cause of death overall in the U.S. in 2014. This was followed closely by cancers, which researchers say were the reason behind more years of life lost to early death than any other disease or cause.

However, the jaw-dropping revelation of the study was the all-time high increase in substance use mortality involving illicit drugs and alcohol during the recent decade. Nearly half of the US counties got an increased incidence of suicide and violence, with deaths from drug overdose seen more rampant in rural rather than in urban areas, Daily Mail reports.

"The mortality trends in mental and substance use disorders, as well as with other causes of death covered in the study, point to the need for a well-considered response from local and state governments, as well as care providers, to help reduce the disparities we are seeing across the country," said Dr. Christopher Murray, Director of IHME, via Science Daily.

"For causes of death with effective treatments, inequalities in mortality rates spotlight areas where access to essential health services and quality of care needs to be improved," lead author Laura Dwyer-Lindgren explained.