According to a new study out of Oxford University, severe mental illnesses reduce life expectancy more than heavy smoking. The research, conducted by psychiatrists, shows that mental illness can reduce someone’s life span by up to 10 to 20 years. People who smoke, meanwhile, typically shave off about 10 years of their life.

“We found that many mental health diagnoses are associated with a drop in life expectancy as great as that associated with smoking 20 or more cigarettes a day,” Dr. Seena Fazel of the Department of Psychiatry at Oxford University, one of the authors of the study, said in a press release. “There are likely to be many reasons for this. High-risk behaviors are common in psychiatric patients, especially drug and alcohol abuse, and they are more likely to die by suicide. The stigma surrounding mental health may mean people aren’t treated as well for physical health problems when they do see a doctor.”

Fazel notes that mental health is often separated from physical health. “Many causes of mental health problems also have physical consequences and mental illness worsens the prognosis of a range of physical illnesses, especially heart disease, diabetes, and cancer.” In addition, people with major mental illnesses may not always have access to proper health care. The Oxford psychiatrists argue that despite the clear impact mental illness has on quality of life and life span, not enough attention has been devoted to mental health services or awareness of the issue, compared to the anti-smoking hype garnered against tobacco companies. About one in four people in the UK will develop some form of mental health issue during the course of a year, and about 21 percent of British men and 19 percent of females smoke cigarettes.

This isn’t exactly breakthrough news; it’s been well-known for some time that people who suffer from mental illnesses tend to have earlier deaths. Nearly 10 years ago, mortality data from Colton and Mandersheid showed that Americans who had serious mental illnesses died about 14 to 32 years earlier than the general population, with the average age being 49 to 60 years old. Dr. Tom Insel, director at National Institutes of Mental Health (NIMH), noted in 2011 that this life expectancy is “on par with many sub-Saharan African countries.”

People with mental illnesses have a higher chance of developing chronic diseases, committing suicide, and substance abuse. People with major depressive disorder have a higher risk for cardiovascular disease as well as stroke; and diabetes patients have a double risk for depression than people who are not diabetic. “We do not fully understand the relationship between diabetes or heart disease and depression, but current thinking attributes the increased risk to both depressive behaviors (e.g., poor diet, low activity, low adherence to treatment) as well as some common biology such as elevated inflammatory factors,” Insel writes on the NIMH blog.

Fazel believes it’s the responsibility of psychiatrists to tackle this issue and to ensure that their patients’ physical health is not neglected. “De-medicalization of psychiatric services mitigates against that,” he notes in the press release. He continues: “All of this can be changed. There are effective drug and psychological treatments for mental health problems. We can improve mental health and social care provision. That means making sure people have straightforward access to health care, and appropriate jobs and meaningful daytime activities. It’ll be challenging, but it can be done.”