Disease vs. Illness
The words “disease” and “illness” are often used interchangeably, but their meanings are very different. Diseases are biomedical entities where there is impairment of the normal functioning of the body. Illness refers to the way a patient experiences a sickness. There can be disease without illness and illness without disease.
Diseases may have external or internal causes. Covid-19 is an infectious disease that occurs when a microorganism in the external environment, the pandemic coronavirus, takes up residence in the body. Diabetes is an internal dysfunction where the body no longer produces enough insulin. There are many categories of disease such as infectious diseases, hereditary diseases, deficiency diseases, and physiologic diseases. Diseases can be classified as congenital or acquired, acute or chronic, iatrogenic (caused by medical treatment) or idiopathic (cause not known). Terminal diseases are those expected to end in death. AIDS was once considered terminal, and it is still not curable; but it has become a manageable disease that patients can live with and that may not even decrease their life expectancy. When the cause of a disease is not understood, it is sometimes referred to as a syndrome or a disorder.
Patients can have a disease and not know it. When patients test positive for Covid-19, many of them are asymptomatic. They have the disease but no symptoms that would make them feel ill. A heart attack may be the first sign of a long-standing cardiovascular disease. The coronary arteries have become increasingly narrowed by atherosclerotic plaques over the course of many years, but the patient remains unaware until a complete blockage or a ruptured plaque deprives heart muscle cells of the essential blood supply they need to function. Only then do the cells begin to die, and the patient experiences chest pain. Conversely, patients may feel sick and be suffering from an illness when there is no actual impairment of biologic functions. One example is hypochondria.
“Dis-ease” is an imprecise term often used in complementary and alternative medicine (CAM) to indicate a vague feeling that all is not well, or to suggest that some optimum condition of “ease” and perfect health is lacking and can only be attained by following the advice of the CAM practitioner.
“Illness” refers to the personal experience of suffering, but it is also a social experience conforming to the norms of society and influenced by culture, education, beliefs, and expectations. Diseases can kill, but illnesses cause most of human suffering through imagination. CAM and mainstream medicine are often at odds because they don’t speak the same language. CAM doesn’t treat disease; it treats illness and cares more about how an individual patient feels than about scientific evidence. It relies heavily on suggestion and placebo effects. CAM sustains hope. Everyone resists the idea that there’s nothing more that can be done. It’s not acceptable to “do nothing,” even when doing nothing is the safest and most reasonable approach. Scientific medicine is often perceived as impersonal, mechanical, uncaring, and as destroying hope. Taking an ineffective CAM remedy lets patients believe they are “doing something.” Patients can benefit from the illusion that they are in control of their destiny and from the positive and caring interaction with another human being.
Cure vs. Healing
Cures are rarely achieved, but healing is always possible. The role of doctors is “To cure sometimes, to relieve often, to comfort always,” an adage that originated in the 1800s with Dr. Edward Trudeau, the founder of a tuberculosis sanatorium (back then, there was no cure for TB, so relief and comfort were all he could offer). In some cases, doctors claim to have cured (for instance, by excising a tumor or removing a foreign body); but in most cases it is really the body that cures the disease, and the doctor’s role is limited to facilitating that process.
“Healing” means different things to different people. Wounds may be due to trauma or surgical incisions, and it is usually obvious when they are healing. The healing process is complex but fairly well understood. First there is an inflammatory phase with a clotting cascade, a response of blood vessels, and the arrival of white blood cells. Then there is a proliferative phase where new tissues replace the damaged tissues. Then maturation and remodeling occur. The healing of a broken bone can be verified by x-ray.
A different meaning for “healing” was brought home to me when I watched a documentary about João de Deus(John of God), a psychic surgeon in Brazil, a charlatan who is currently in prison for sexually abusing 600 women, including his own daughter. They interviewed a woman in Italy who had travelled to Brazil to be treated by him and who firmly believed he had healed her. She had advanced metastatic breast cancer and had stopped the conventional treatments of her oncologist when she decided to see the psychic surgeon. She died in 2003. At the time of the interview, her disease was progressing, and she was dying of cancer, yet she claimed to have been healed. Was she in denial? Didn’t she realize the cancer was killing her? What was she thinking? Was this a triumph of hope over reality?
I eventually understood that by “healing,” some people mean a psychological process where they have come to terms with their diagnosis. They have achieved acceptance and are no longer distressed. An article in the Annals of Family Medicine explains:
“Healing was associated with themes of wholeness, narrative, and spirituality. Healing is an intensely personal, subjective experience involving a reconciliation of the meaning an individual ascribes to distressing events with his or her perception of wholeness as a person.”
Their conclusion: “Healing may be operationally defined as the personal experience of the transcendence of suffering.” OK, but measuring that personal experience is problematic. That concept of healing is hard to pin down, and it relies on patient self-reporting. It is more of a metaphysical concept than a scientific one.
Pain vs Suffering
There is no convenient objective way to measure pain. We can only accept a patient’s report that they are experiencing pain. We ask them to rate their pain on a scale of one to ten, where ten is the worst pain, zero means no pain, and anything over 8 is considered severe pain. I hate it when I am asked to rate my pain on that scale; it lacks nuance. I never know what to say, and my answer will vary depending on my mood. What should I answer if I am pain-free at the moment, but the pain was bad enough to keep me from sleeping last night? What if I wouldn’t call it pain but simply discomfort? What if a patient is a stoic who never complains? What if the patient is a person who habitually exaggerates or imagines symptoms? What if they report a pain level of 15 out of ten? A good clinician can investigate by asking questions like “Do your teeth itch? Do your stools glow in the dark?” If patients answer yes to all such questions, the doctor will know to discount their reports as unreliable.
Pain is a physical sensation; suffering is a psychological one. Pain can occur without suffering, as in the famous movie scene where Lawrence of Arabia extinguishes a match with his bare fingers and explains that the secret is not minding that it hurts. And suffering can occur without pain. Anticipation of pain often causes more suffering than the pain itself. “Pain and suffering” is a legal term used in the courts to help determine monetary compensation for injuries.
Suffering is determined by the sufferer’s thoughts. People try to interpret the meaning of their pain. For Lawrence of Arabia, the pain in his fingers meant an opportunity to impress other people. Can you expect the pain to be over soon? Will it soon stop with a desirable outcome like the birth of a baby? Does the pain mean you are going to die? Can you expect the pain to get worse?
Veterinarians claim to know when an animal is suffering, but they don’t have access to the animal’s thoughts. They are limited to observing the animal’s behavior. If an animal stops eating and is less active, what is going on in their mind? Do they experience suffering, or do they merely feel the experience of not wanting to eat or move? Animals live in the moment, not in the past or future.
For that matter, is a crying baby experiencing suffering, pain, or just frustration? Is crying a way to manipulate adults into satisfying their needs with a diaper change or a feeding? Animals and newborn babies don’t have the mental development to think like adult humans. Newborns are incapable of obsessing about past instances of pain or anticipating future suffering. They are incapable of speculating about what the pain might mean. A new baby may cry when blood is drawn, but they also might cry just as vigorously when being restrained or having their clothing changed.
When I was an intern, two patients on our surgical ward had the same operation (inguinal hernia repair). One was an adult who continued to complain of pain for days and refused to get out of bed; the other was a toddler who was happily running around the ward right after the surgery. The toddler had no expectation that he would be incapacitated by pain; the adult was unduly worried and avoided doing anything he imagined might cause more pain.
Hypnosis could be thought of as “mind over matter.” It can reduce the experience of pain through selective attention/inattention; the suggestions of the hypnotist direct the patient’s thinking. Similarly, natural childbirth utilizes thought control and distraction to reduce the need for anesthesia or drugs.
Things to remember
Words matter. Improving the precision of our language should improve the clarity of our thinking.
Science-based medicine treats diseases, CAM treats illnesses. (This explains a lot!)
Healing is an elastic term that may not mean what you thought it did.
Suffering is not the same as pain. Each can occur without the other.
This article was originally published as a Reality Is the Best Medicine column in Skeptical Inquirer