The debate about what mental states should qualify as a true disease is always lively. Furthermore, it heats up every time a new version of official classifications comes out, such as the (DSM) or the International Classification of Diseases (ICD), the latter of which made news last year for its inclusion of entities like " ."

One of the things that keeps the controversy going is that there is unlikely to be any way to determine the correct answer. Words like “disease” or “illness” or “disorder” are, well, words that we have created. Nevertheless, the categorization of certain mental states as certified diseases does have very real implications when it comes to things like stigma, insurance coverage, and research funding.

Recently, a group of researchers in Finland conducted a large survey to gather opinions on what mental states should be called a disease from four groups of people:

Lay people in the community with no prior training in medicine Members of the Finnish Parliament Nurses Physicians, with about 10 percent of them being psychiatrists

The survey was fairly simple in that it asked respondents to rate, on a five-point scale, how much they agreed with 20 different mental states being considered a disease. Those states were the following.

Anorexia Gambling Drug addiction Work exhaustion Transsexualism Premature ejaculation Absence of sexual desire

Overall, the study found that there were some pockets of agreement, but quite a bit of variability of opinion that partially was attributed to which group you were in. Autism and schizophrenia were the two entities which nearly everyone in all groups rated as a disease, while few respondents in any group rated grief or homosexuality as a disease. Psychiatrists, non-psychiatrist physicians, and nurses tended to see more mental states as diseases than laypeople and members of parliament, although they were also somewhat more likely to rate things like grief and homosexuality as non-diseases. Transsexualism was generally rated as not a disease, with nurses being the group that was most unified in their view (close to 85 percent of nurses rated transsexualism as not a disease).

For many topics, there was much wider disagreement between and within groups. About half of lay people, for example, stated that gambling addiction was not a disease, compared to only about 10 percent of psychiatrists. The majority of physicians (psychiatrists included) viewed disorder as a disease, compared to only about 25 percent among parliament members.

Interestingly, ADHD was generally seen as a disease by about 75 percent of all groups despite the diagnosis being somewhat controversial in places like the United States. Beyond the different groups, younger people and women were somewhat more likely to view these states as diseases compared to older individuals and men.

If you are interested in seeing how your opinion matches up with others, the full article is available for free (see reference). One thing to keep in mind is that the people who completed this survey were in Finland, and it is quite likely that respondents from other countries might provide substantially different data.

The survey leaves out questions about where to draw the line within a particular diagnosis. In other words, even if you think social disorder is a legitimate disease, you may differ with others regarding how severe the thoughts, feelings, and behaviors have to be to cross the line from shyness into social anxiety disorder. This debate will, of course, go on (and if you are really interested, I wrote a book on thinking about the boundary between traits and disorders).

For many people, a disease requires some kind of pathological entity or process that can be readily identified, like invading pneumonia in a lung or a blockage of a heart blood vessel. This kind of clarity has been hard to find definitively, even for conditions like autism or schizophrenia, where there is general agreement about meeting the definition of disease. Part of the issue, as suggested above, may be that most things in mental health exist as dimensions rather than categories, so the question becomes when is there too much or too little of something to constitute a disease or a disorder.

This characteristic of mental health conditions has been used by some to critique psychiatric conditions as “not real,” thereby increasing stigma and in the process. This is misguided, as the neurobiological basis of mental functioning at all levels is extremely well established. It is also worth remembering that many of the most common non-psychiatric diseases (hypertension, high cholesterol, type 2 diabetes) also exist dimensionally with unclear lines between disease and non-disease state—but without all the public criticism that such conditions don’t actually exist.

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