People with asthma are more than twice as likely to have depression or anxiety as people who don't have the chronic airway disease, according to a new study. To make matters worse, researchers found that when rates of serious psychological distress went up, health-related quality-of-life scores went down.

The researchers reviewed data from 186,738 adults who had participated in the US National Health Interview Survey between 2001 and 2007. From this database, they discovered that the rate of asthma was 7%.

Among all of the study participants, the average prevalence of serious psychological distress was 3%, but in people with asthma, the rate of serious psychological distress was 7.5%, the researchers found.

Adults with asthma who had other chronic conditions, a history of smoking or alcohol use, and those with a lower socio-economic background had a greater risk of having serious psychological distress.

"The prevalence of serious psychological distress was 2.5 times higher among adults with asthma, and as serious psychological distress increased, health-related quality went down... and together they synergistically make quality of life even worse," said study senior author Dr David Callahan, a medical epidemiologist at the US Centers for Disease Control and Prevention and the US Public Health Service in Atlanta.

Study author Emeka Oraka said these findings may apply to other chronic diseases, such as diabetes, and that serious psychological distress may make it harder for people to manage these diseases properly.

"Any kind of mental distress impedes your ability to manage the disease well, whether it's asthma, diabetes or something else," said Oraka, who's an Oak Ridge Institute for Science and Education fellow at the CDC.

Oraka noted that the findings should raise a red flag for clinicians. "Serious psychological distress is a powerful predictor of quality of life, and even more so in the presence of chronic illness," he said. "Don't disregard the importance of mental health in the quality of life of patients with chronic illness."

Oraka said that the study wasn't able to find out whether asthma is a cause of serious psychological distress or whether asthma medications may make serious psychological distress more likely. "This study found an association, but no causation," Oraka said.

"As with any chronic disease, asthma needs to be managed carefully by the patients, and serious psychological distress can get in the way of people managing their own asthma," explained Callahan.

"Clinicians need to ask about psychological symptoms in people with asthma, and they need to treat both psychological distress and asthma."

Pic: Nick Winchester