Focus on depression
At the University of Calgary, AHFMR Health Scholar Dr. Scott Patten's research activities lie within the discipline called psychiatric epidemiology. This relatively young field involves studying the distribution of mental illnesses in large groups of people in order to better understand the conditions. Dr. Patten's particular interest is the epidemiology of depression and its association with a variety of chronic medical conditions. "The fact that depression is associated with other illness is only a crude piece of information," he explains. "The association could mean that illness causes depression, that depression causes illness, or that one affects the prognosis of the other. So while the association is interesting, it's not particularly informative. We need to know more."
One side of this association seems intuitive: that sickness could contribute to depression. The other side-that depression can increase the risk for chronic medical conditions-is not so obvious. This is where Dr. Patten's research has come up with some surprising results. His team found that depression has a strong impact on the risk or onset of various chronic medical conditions including heart disease, high blood pressure, chronic lung disease, migraine, arthritis, and chronic back pain. In other words, people with depression have a higher risk of developing certain diseases that they did not have before. For some conditions-including high blood pressure, heart disease, and migraine-the risk doubles. No link was found between depression and thyroid disease, peptic ulcers, cataracts, or glaucoma. Dr. Patten notes that there appears to be a pattern linking depression with conditions involving inflammation and chronic pain.
"The idea that depression could affect disease risk is very new. There's very little literature about it," says Dr. Patten. "If we can understand this more fully, there are important implications for the treatment of a variety of diseases."
For example, research has shown that depression increases the risk for type 2 diabetes. But the converse is not true: type 2 diabetes does not affect the risk of depression. Dr. Patten says this likely means that people who are struggling with depression are going to need new types of assistance to ensure they address such risk factors for diabetes as lack of exercise, overweight and obesity, and smoking. The situation is different for people with multiple sclerosis, where the disease itself plays a big role in increasing the risk of depression. These people will require specialized mental-health services.
"We're just starting to unravel the complexities that link mental and physical illness," says Dr. Patten. "I'd like to see a more holistic view of healthcare, so that the mental-health domain fits better with the non-psychiatric medical system in a way that would best help people. The mental-health field has to work harder to prevent related health problems."
What is epidemiology?
Epidemiology is the study of how often diseases occur in different groups of people and why. Epidemiological studies can identify risk factors for disease and determine which treatments work best. Because epidemiological observations relate to groups of people, they are different from clinical observations, which determine decisions about individuals.