Have I piqued your interest or accidentally insulted you? I did not make this question up. Thinkers and physicians for many years have wondered the same thing. Mental illness is confusing. It is not diagnosed as is physical illness via tests for microbes, probing for damaged or diseased tissue, nor compiling a list of objectively measurable symptoms. Mental illness is diagnosed via a system of symptom clusters published in one or another manual, the contents of which are agreed upon by scholars in the field. The problems arise when the contents of those manuals change over time, because mental issues are not clear-cut diseases as are physical illnesses. Things are added and subtracted over time--but we could not imagine a time when influenza would stop being called a disease!
Science tries, year after year, to isolate specific markers for mental illness. Tests come and go, but the construct remains elusive. We can objectively test for the flu or cancer or diabetes or a broken leg, but we cannot test in a way that never changes, for depression, schizophrenia, or anxiety.
This does not mean that you are not suffering with your problem. It only means in this context, that your problem is mislabeled by being lumped in with physical illness. This is important for many reasons. I hope you are still with me as I elucidate why I, and others like me, believe calling mental problems "diseases" hurts those who suffer with them.
Despite years of using these new labels and making depression and alcoholism diseases, we are no closer to a solution. I do not say "cure", only because that word is used to refer to the removal of a disease. I like the word cure, as it implies a final exorcism of the problem, but I do not like that it then throws the problem back into the language of disease. If depression is like flu, then you can either wait until it gets better, and it ought to run a pretty specific course, or you can perhaps get vaccinated at a young age and never become depressed. This, of course, does not make sense. Depressions often do remit over time, but it can be too difficult to handle the suffering meanwhile, and, despite pharmaceutical advertising to the contrary, there are no medications developed to alleviate symptoms while you wait.
You can indeed take one of many antidepressant medications, but there are a couple of problems with this approach. One is that they tend to have bad side effects. This is one reason drug trials with antidepressants are mostly unreliable--people can tell if they are on the placebo or the medication due to side effects, and in comes the placebo effect and they feel better. A second problem is that the theory of why they work is patently false. We do not know enough about neurotransmitters in the human brain to make direct cause-and-effect claims like "when you take a selective serotonin re-uptake inhibitor your brain is normalized by keeping more serotonin available". The brain compensates for the presence of excess serotonin, making this claim false on one end, and we actually have no proof that depression is causally linked to a lack of serotonin, making it false on the other.
This does not mean you are crazy if you take one and feel better, just that the evidence that these medications cure something is not really there. For some, the symptoms do remit for a while while taking such drugs. That, unfortunately, is not a "cure"; it is a respite from a part of your symptoms; an aberration from your normal brain chemistry that is tough to repair later.
What about alcoholism? One thing that becomes increasingly clear over time is that addictions often co-vary with other mental problems such as depression, trauma history, or anxiety. While there is often a genetic component to these problems, some of which is metabolic, a complicating factor is that we can learn how to use a substance to escape from problems from those around us, making sorting genetics from environment very tricky. There are medications that can help you avoid using your substance of choice, but are there any for the symptoms, so that you can wait patiently, feeling okay while your disease remits?
Thus, the first reason to avoid calling depression or addiction diseases is that calling them that and treating them as such does not help you get better.
A second reason to avoid labeling mental issues or symptoms as diseases is that this removes your feeling of owning the power to improve. If you have a genetic problem or a chemical imbalance in your brain, it could be impossible for you to effect change by some action you take. If, on the other hand, mental problems have a variety of causes, you can begin to root out those causes and make changes in your personal experience. For some, having a guiding therapist helps, but many people use books, seminars, articles, or simply self-awareness to help themselves.
What about problems in childhood? ADHD--Attention Deficit Hyperactivity Disorder, prevents kids from doing well in school, makes them difficult to handle, and prevents them from living successful lives, right? So the only solution is to medicate them and help them to fit in and do what they're told. Maybe. What if ADHD is not one thing, but many things, and some of them are normal. Children are supposed to play and explore and misbehave and test limits. The environments in which we place them at very young ages tend to discourage such behaviors. This is not to say that no child is an outlier who is more active or less attentive than her peers, just that fidgeting and impulsivity are hallmarks of childhood, and we ought to be less eager to call them symptoms. Additionally, given the rampant side-effects from stimulant medications, we as a culture ought to be more flexible in learning how to help such children without chemical assistance. We ought to be differentiating the symptoms of lead poisoning, head injury, or severe trauma and anxiety from behaviors that annoy us. Just because a child does not fit the public school model does not mean he is ill.
What if you have suffered a terrible trauma or a neglectful childhood? You have genuinely suffered from injuries to the psyche, and you are in emotional, or even physical, pain. Why would I not count the symptoms you have, from PTSD (Post-Traumatic Stress disorder) to dissociation to depression, as illnesses? My reasoning remains the same. There is no disputing the fact that trauma, early or late, can lead to debilitating symptoms, but when I call it a disease, you might feel trapped by your past experiences and unable to help yourself heal. This is in no way meant to diminish the damage caused by abuse or neglect or trauma, but to call the results by another name in an attempt to empower those who have suffered to learn the path to healing.
Disorders of the brain such as Parkinson's disease, stroke, and tumors exist, but these are not my subject today. Such physical ailments of the brain can also cause emotional or behavioral symptoms, but not all behaviors we do not like are symptoms of disease. The trouble with the label of mental illness is that calling everything a disease distorts both the construct of disease and the process of getting help.
Because what I do under the label of psychotherapy is to empower clients to solve problems, the language of "mental Illness" is contrary to my intent. I do not have the power to heal you with a drug or a surgery; there is no magic bullet. What competent psychotherapy can do is to guide you to help yourself feel better with empathy, information, skills practice, and occasional sound advice. To me, the question is whether you wish to be a patient with a mental illness or a client with a desire to solve your own problems. Getting help to solve a problems is just as logical as having someone else repair your car or your plumbing--You are ultimately getting the work done, but you may require expert assistance. Do not discount your own power to solve problems and feel better.
Kirsch, I., The Emperor's New Drugs: Exploding the Antidepressant Myth Basic Books, 2010
Szasz, T. S., The Myth of Mental Illness: Foundations of a Theory of Personal Conduct , Harper Collins, HarperCollins 1960.
Whitaker, R., Mad in America: Bad Science, Bad Medicine, and the Enduring Mistreatment of the Mentally Ill Basic Bookis, 2001