Pneumonia is a disease, but grief is not. What about dental cavities? The limits of disease are difficult even for doctors to define.

Diseases are defined in international classifications of disease, treatment recommendations, research and conferences. The ultimate distinction between disease and normality in practice is made by doctors when they write diagnoses for their patients.

In everyday use disease is a simple word, but an exact definition is difficult even for experts in the field.

University of Helsinki researcher and clinical epidemiologist Kari Tikkinen co-wrote an article entitled “What is a disease”, which was published in the BMJ Open journal last winter. In the study, 6,200 Finnish laypeople, doctors, nurses and members of parliament were presented with 60 different human afflictions and asked, “Is this a disease?”

The doctors were more eager to classify the problems as diseases, but even among them there was much disagreement on many points. For example, 55% of doctors considered drug addiction a disease, and 51% thought the same of lactose intolerance.

Industrial diseases

Kari Tikkinen became interested in the concept of disease while working on his doctoral dissertation. He was studying a disease known as overactive bladder syndrome, and began to question the logic behind the diagnoses. According to Tikkinen, overactive bladder syndrome has been marketed as a disease by the pharmaceutical industry.

“The symptoms are too generalised to qualify as a disease, and a diagnosis may be completely useless for patients. In the worst case, such diagnoses draw attention away from the true causes of the symptoms.”

The description of the syndrome includes the sudden urgent need to urinate, urinating at night, incontinence and the need to urinate more often.  Night-time urination is a particularly poor fit for the syndrome, as its causes typically lie elsewhere than the bladder.

Overall the causes for urination-related afflictions are still largely unknown, and overactive bladder syndrome cannot be diagnosed based on symptoms.

“Medication for the symptoms exists, but is rarely sufficiently effective and often carries side effects,” states Tikkinen.

A total of 57% of the laypeople participating in the study considered an overactive bladder to be a disease, while 75% of doctors agreed.  Night-time urination, a similar problem, was deemed a disease by 40% of the laypeople and 46% of the doctors.

“Night-time urination has not been marketed as a disease as strongly, and it doesn't sound as medical as overactive bladder syndrome.”

More on the definitions of diseases and the survey responses in Tikkinen’s study (in Finnish) in the new Yliopisto magazine. The theme is continued  (in Finnish) in the panel discussion organised by Yliopisto magazine, entitled “Sairasta vai tervettä” (“Healthy or sick”) on 10 September at 16.00–18.00 at the University of Helsinki Think Corner (Yliopistonkatu 3).

The panel is part of the magazine’s 60-year celebration. The interviews, panel discussions, research meetups and coffee events organised in Porthania are all open to the public; welcome!