An ever growing body of evidence is suggesting that depression, and other forms of mental illness, can be linked with physical conditions like bowel and skin diseases. While it’s clear that mental disorders are associated with a higher incidence of physical conditions, how generalized (over a range of physical health outcomes) these associations are is far less clear.

A recent study by psychologists at the University of Basel and Ruhr University Bochum has identified temporal patterns in the mental and physical state of 6,500 young people. In particular, the study links arthritis and digestive system diseases with depression, anxiety with skin disease and others like epilepsy with eating disorders. Previously, evidence linking physical and mental disease was largely on a single-case basis, but for the first time it has been formally noted that the two are correlated, with physical diseases occurring more frequently in adolescents having previously suffered a mental illness. Interestingly, the same might be said about mental disorders occurring after the onset of particular physical diseases. Diseases relating to moods, feelings or attitudes like depression often saw the development of arthritis or digestive diseases, while anxiety disorders were more common with people with a history of heart disease.

Another study looked at the association of 16 specific mental disorders with the subsequent onset or diagnosis of 10 chronic physical conditions. The cases were spread across 17 countries, with the main outcome of the study being that all kinds of mental disorders were associated, at least in part, with a significant risk of developing one of a wide range of chronic physical conditions. The authors suggest that current efforts to improve the physical health of individuals might be too narrowly focused on a small group of the most severe mental disorders, while it might be more optimal to consider integrating physical health considerations into the treatment of all mental disorders, as early as possible.

These studies offer insight into the causal relationship between physical and mental disease, throwing light on the processes that are relevant to their origins and perhaps how to better treat them individually, or even together. The results of these studies, and others, are likely to cause many to doubt the effectiveness of what can only be described as the appalling treatments that exist for many serious mental diseases. Arguably, we’re not advanced in the areas of physical science, philosophy or psychology to fully explain the interaction between physical and mental disease, or how to properly cure them. That said, now that the relationship between them is better established, we might better anticipate mental or physical disease in all their forms. The origins of one might well stimulate the onset of the other, and perhaps more study into the nature of this relationship will lead to better treatment, and ultimately prevention of the crippling and cyclic nature of mental and physical disease.