My younger sister Sarah has always been a positive and bubbly girl, but since the beginning of her life she has had many medical issues. Her doctors believed that she would never be able to walk, as she suffers from low muscle tone and Pseudohypoparathyroidism, which affects her body’s ability to absorb calcium and iron properly. She was in physical therapy from the age of 18 months to 7 years old. Besides these issues, there was something else wrong with Sarah that the doctors could not figure out for a while. Doctors thought she had Celiac Disease, and our diets instantly became gluten free. When that didn’t solve the problem, her doctor’s realized that her Celiac test resulted in a false positive. It wasn’t until the age of four that my sister was diagnosed with Crohn’s disease. Crohn’s disease is an autoimmune disorder that affects the gastrointestinal track, and can cause many other issues, such as stunted growth, blockage of the bowel, and a weakened immune system (Crohn’s Wikipedia Page).
Despite all of these issues, my sister Sarah has done remarkable things. She does well in school, is a member of a competitive dance team, and plays multiple instruments. However, recently, her Crohn’s has been flaring up, and she has had to have many iron transfusions as well as change around a lot of her medications. I feel as if this could be a stressor for anyone, but I have noticed my sister’s attitude changing. She doesn’t enjoy school, dance, or violin anymore. She tells me she comes home crying everyday and all she wants to do is watch TV. These are very telling symptoms of depression, which is not typical of my bubbly and charismatic sister. This makes me wonder: Is Crohn’s disease causing my sister to be depressed? Well, it turns out that there have been studies done on both children and adults with Crohn’s disease to test this theory.
The direct causation relationship in this case is that Crohn’s disease causes depression. In a study funded by CCFA, 276 kids aged 9-17 with Crohn’s disease were followed for 6 months. At the beginning of the sixth months, the children were asked to report the level/severity of their Crohn’s and answer questions about their metal state, specifically about depression and anxiety. At the end of the 6 months, the children were asked to answer these same questions again. The study showed that children whose Crohn’s got better reported better mental health, and the children’s whose disease worsened had worsening mental health, with a reported p value of less than .005. This strongly suggests a correlation, but since it was an observational study with self reported answers it is hard to determine causation. I feel if this study were done with a larger amount of subjects, over a longer period of time, and the subjects reported their disease and mental health status more often over the length of the study, the results would provide stronger evidence of a direct correlation between Crohn’s and depression.
The reverse causation in this relationship would be that depression causes flare ups in one’s Crohn’s disease. In this study published by the American Journal of Gastroenterology, 2,144 adults with Crohn’s disease were followed for 12 months. At the beginning of the study, the participants reported the severity of their disease as well as any mental health issues. Throughout the twelve months, the participants’ were followed and data was recorded about their flare ups, specifically hospitalizations, and their levels of depression before and after hospitalization. The study concluded that those with depression had more aggravated symptoms are were hospitalized more often, with a reported p-value less than .001. The conclusion of this study strongly supports the reverse causation relationship, however since it’s an observational study it is hard to rule out confounding variables.
Obviously, there are many confounding variables that could make someone depressed, such as family issues, a genetic predisposition, and abuse. Not to mention that depression is pretty common among people with chronic illness. Since both of the studies I mentioned are observational, any and all of these confounding variables could be at play. Let’s not forget that chance is always a possibility as well.
So, what does all of this mean? Well, I was personally surprised to find that reverse causation in this situation was more likely than I thought. However, the study that showed reverse causation only focused on adults, so it probably doesn’t apply to my 15 year old sister. However, the study done on children that showed direct causation seems applicable to my sister, seeing as she has recently had changes in medication due to flare ups and in turn her recent change in behavior.
So all in all, I think it is safe to conclude in my sister’s case, her Crohn’s flare ups are causing her to be depressed. In general, there seems to be a correlation between depression and flare ups in Crohn’s, with a reverse relationship in adults, and a direct relationship in children.