People who have both binge-eating disorder and a mood disorder are more likely to have a more severe form of the former, according to a new Yale study.

Researchers studied 347 patients, all of whom had binge-eating disorder, characterized by the DSM-IV as repeated episodes of both eating more than what other people would consume during a similar time interval in similar circumstances, as well as a sense of lack of control during that interval, with feelings of distress throughout. These patients were evaluated and then divided into four categories — those who also had a mood disorder, those with a substance abuse disorder, those with both and those with neither. The study found that BED co-occurs frequently with both mood disorders and substance abuse disorders.

The research showed that patients with both BED and a mood disorder, such as depression, were more concerned when thinking about their eating habits, their weight and their body shape than those without a mood disorder.

Researchers noted that BED is often not considered when people consider eating disorders.

“There’s a fair amount of interest, certainly in my lifetime, about eating disorders generally,” said Daniel Becker, a clinical professor of psychiatry at the University of California, San Francisco and lead author of the study. “The two kinds people most commonly think and talk about are anorexia nervosa and bulimia nervosa — binge-eating disorder is actually more common than the other two put together.”

Becker cited a 2007 study that estimated the lifetime prevalence rates of anorexia nervosa to be 0.9 percent among women, with bulimia nervosa and BED at 1.5 percent and 3.5 percent, respectively.

Binge-eating disorder has only recently been established as a recognized mental disorder, Becker said. The American Psychiatric Association officially included binge-eating disorder in the DSM in 2013.

Fifty-four percent of patients in the study were found to have a mood disorder in addition to having BED. Those patients were found to be more likely to have a personality disorder as well as a heightened sensitivity to eating, weight and shape concerns.

Becker said that, in addition to helping researchers better comprehend problems related to BED, such as obesity and overeating in general, studies like this can help to discern whether comorbidity — when two chronic conditions occur together — of these disorders is random, or if there is a relationship between the disorders. He added that answering that question can help them understand whether there is a shared mechanism that causes both disorders or whether one disorder causes the other.

According to Peter Morgan, professor of psychiatry at the Yale School of Medicine, recognizing the subtypes within BED is important for finding more specific treatment approaches that can be personalized per patient.

Kimberly Dennis, CEO and medical director at Timberline Knolls Residential Treatment Center — a mental health and substance abuse treatment center — agreed. She added that by relegating one disorder of a co-occurring set of disorders to a “secondary” diagnosis, and neglecting to treat that secondary disorder properly, is “not a recipe for sustained recovery in the long term.”

Both Becker and Dennis stressed the chronic nature of disorders such as BED and mood disorders. Becker said further studies might look at how comorbid disorders affect each other over time, or what the differences might be depending on which disorder begins first.

“Those interactions over time are things that we don’t have much of an understanding of,” Becker said. “Another way we could go [is to look at] temporal or causal sequences, and try to understand how that works from a psychopathology point of view. Eventually all of this is aimed at helping people.”

Dennis said studying the co-occurrence of BED with other disorders is also important because clinicians need to be cross-trained to address this comorbidity, as opposed to treating the disorders separately.

Likewise, the billing process of insurance companies is not set up to recognize comorbidity, Dennis said. It instead bills patients by naming one of their disorders as primary and the others as secondary or tertiary.

“It’s a complex package,” Dennis said of comorbidity.

Morgan noted the study’s inconclusive results on any relationships between BED and substance abuse disorder. He added that the researchers also did not look at whether eating disorders share more similarities with mood disorders or with substance abuse disorders.

According to the National Institute of Mental Health, 9.5 percent of U.S. adults have some sort of mood disorder.