People with bipolar disorder are four to six times more likely to die prematurely than those without the condition, according to a study that compared data on thousands of people with and without the disorder.

What really puts the results in perspective is that bipolar disorder increased a person's risk of death far greater than a history of smoking, or even, to some extent, age.

The research team analyzed data from a large, long-term study, called the Prechter Longitudinal Study of Bipolar Disorder, as well as data from anonymous patient records collected at University of Michigan Health clinics.

The Prechter dataset included observational data of 1,128 participants, 847 with bipolar and 281 without.

Data from the clinics included 18,561 patients, 10,735 with bipolar and 7,826 without.

In one of the two data sets the University of Michigan researchers analyzed, a diagnosis of bipolar disorder meant someone was six times more likely to die during a 10-year period than a person without the disorder.

By comparison, in that same cohort, a person's mortality risk was 2.3 times greater if they were over 60 years of age. And the mortality risk for people with a history of smoking was 2.5 times higher than those who never smoked.

University of Michigan psychiatrist Melvin McInnis, who directs the Prechter program and was a co-author on the paper, says he was surprised by just how high the risk for premature death was for people with bipolar disorder.

"In both samples we found that having bipolar disorder is far more of a risk for premature death than smoking," he says.

"Over the years there have been all kinds of programs that have been implemented for smoking prevention and cardiovascular disease awareness, but never a campaign on that scale for mental health."

Bipolar is a category of mood disorder diagnoses, listed in the DSM-5, which is used to describe clusters of symptoms that can seriously affect a person's quality of life.

People with bipolar disorder experience distinct 'high' (manic or hypomanic) and 'low' (depressive) periods that last for several days or weeks, though these episodes generally occur between periods of normal mood.

Both manic and depressive episodes carry risks for the people who experience them, which can affect their lifespan. At the manic pole, feelings of euphoria, impulsivity, distractibility, and agitation can lead people to make risky and sometimes dangerous decisions. At the depressive pole, health and hygiene can fall by the wayside and there's a higher risk for self harm and suicide.

While deaths by suicide are more obviously attributable to mental illness, the study highlights the indirect impact that bipolar can have on shortening a person's lifespan by up to 8-10 years.

In 2021, the CDC leading causes of death report did not include any psychiatric illnesses, which as the authors point out, is because the reported cause is always the most immediate condition (things like heart disease, stroke, or liver disease). Their findings may help address this gap in understanding how a psychiatric illness like bipolar disorder can take years off a person's life.

For instance, accidents (unintentional injuries) are a leading cause of death, which people are at higher risk of during manic episodes. Cancer is also a leading cause of death, and since up to 70 percent of people with bipolar smoke (much higher than the worldwide average of 20 percent), they are also at higher risk of cancers associated with smoking.

"Bipolar disorder is never going to be listed on the death certificate as the main cause of death, but it can be an immediate or secondary contributor to a death," biomedical researcher and lead author Anastasia Yocum says.

For instance, in the Prechter cohort, people with bipolar were significantly more likely than those without a diagnosis to have other simultaneous health conditions including asthma, diabetes, thyroid conditions, high blood pressure, migraine and fibromyalgia.

"We need to know more about why people with bipolar have more illnesses and health behaviors that compromise their lives and lifespan and do more as a society to help them live more healthily and have consistent access to care," McInnis says.

This study was published in Psychiatry Research.