What Do We Mean by Quality of Life?

Despite the strong sense that we understand what QOL is, the term currently defies precise description. This is because QOL is a personal, private, subjective experience; has no ‘normal,’ ‘average,’ or any other frame of reference; lacks any units of measurement; and means different things to different people. In animals, QOL is not restricted to what kind of housing the animal has, the type of food he gets, the luxuriousness of her bed, the number of walks he gets per day, what size of yard she has to play in, whether he goes to doggie daycare or stays home alone all day, or whether she has animal companions to play with. And, most important, it is not restricted to—or equivalent to—his health status. It is a compilation of all of these factors and more, and the animal’s reaction to and feelings about them. So what do we mean by quality of life in animals? It can best be understood as one’s level of enjoyment of life. In this way, we can view QOL in many ways as very similar (though not quite identical) to happiness.

The Feelings of Quality of Life

Quality of life in animals appears to be comprised of the balance between pleasant and unpleasant feeling states—known as the affect balance model. In this view, QOL may be seen as scales, with pleasant feelings on one side and unpleasant on the other. The direction of tipping of the scales represents the individual’s QOL. Quality of life increases when the balance tips toward the pleasant feelings, and declines when the balance tips toward unpleasant feelings. A key feature of the affect balance model of QOL is that it becomes very clear as to which factors in life contribute to QOL. Anything which tips the QOL scales—in either direction—plays a role in the animal’s QOL; but those things that do not tip the scales do not affect the animal’s QOL.

Major Contributing Factors to Quality of Life

Several factors contribute to QOL, all having their influence through their associated pleasant and unpleasant feelings. Those with the greatest influence include:

• Social relationships—Social bonds are promoted and enforced by pleasant and unpleasant emotions. Positive social affiliations and companionship elicit pleasant feelings, and separation and isolation elicit unpleasant feelings.
• Mental stimulation—Monotonous, unchanging environments elicit highly unpleasant feelings of boredom. Conversely, pleasant feelings are elicited by stimulation, challenges, and mental engagement.
• Health—Compromised health involves a wide array of unpleasant feelings. Physical disabilities limit one’s opportunities for experiencing pleasurable feeling states.
• Food intake—The pleasant taste of food and the unpleasant feeling of hunger both motivate consumption of nutrition to support life, and both may contribute to the animal’s QOL.
• “Stress”—As a contributing factor to QOL, stress refers broadly to specific unpleasant emotions such as fear, anxiety, loneliness, boredom, and anger. Its influence on QOL is through the feelings associated with these emotions.
• Control—In animals and humans, one of the strongest predictors of well-being is the perception of control over meaningful aspects of one’s life. The opposite—a sense of lack of control—is associated with feelings of helplessness and depression and lowered enjoyment of life.

Maximizing Quality of Life—General Principles

Maximizing QOL can be summarized by a single principle: Tip the QOL scales as far toward the pleasant side as possible. Based on the balance model of QOL, this may be achieved by minimizing unpleasant feelings, promoting pleasant feelings, or a combination of the two. This basic principle applies to all animals, healthy and ill. For animals with a health disorder, the main effort is to restore a diminished QOL by alleviating the unpleasant feelings associated with the disease. For animals with disabilities, this most often means restoring or replacing the impaired function in order to regain lost pleasures in life. For healthy animals, the main emphasis is promoting pleasures. In all cases, QOL rises as the scales tip increasingly toward the positive direction.

Maximizing Quality of Life in the Ill Animal

In the ill animal, the QOL balance is tipped toward the unpleasant side because of (1) the increase in unpleasant feelings associated with the disease state, which may consist of a single high-intensity discomfort or multiple low-intensity discomforts; (2) a diminished ability to enjoy pleasant feelings and experiences due to the tendency of unpleasant feelings to focus attention progressively more on the discomfort and progressively less on pleasant feelings; and (3) the impaired opportunities to experience pleasure due to the disabilities associated with the medical disorder. Because of the powerful effects of the unpleasant feelings, the emphasis of maximizing QOL in the presence of disease is directed toward the alleviation of the discomforts associated with the disease. Restoration of health is the most effective means to regain the diminished QOL, but also effective is alleviation of unpleasant feelings when cure is not attainable. Numerous interventions may help achieve this objective; for example, medications and oxygen supplementation to aid oxygenation, analgesics, antiemetics, laxatives, anxiolytics, antihistamines, corticosteroids, chemotherapy agents, and gentle and soothing human contact such as stroking, petting, and talking to the animal (which research suggests can attenuate feelings of pain, anxiety, fear, and loneliness). Attention should be prioritized according to the distress potential of the specific unpleasant feelings.

It is also crucially important to include mental health and well-being in the spectrum of animal health disorders. Emotional illnesses, such as phobias and separation anxiety, elicit unpleasant feelings as distressing as physical illness. Although the primary focus for QOL in ill animals is the alleviation of unpleasant feelings, the vastly underappreciated potential for QOL maximization—a key element to tipping the QOL scales toward the pleasant side—is the promotion of pleasant feelings. Providing the ill animal with more pleasurable experiences will enhance QOL (this is what “pampering” is—an effort to flood the animal with pleasurable feelings). Sources of pleasurable feelings include social interaction and companionship (with humans and other animals), mentally stimulating and engaging activities (variety, challenges, play, chase-and-pounce games, fetch games, hunting for hidden objects and food treats, outings, interactive toys, leash walks outside, a continuous supply of novel objects to investigate and explore such as cardboard boxes, tree branches, objects), taste pleasures (palatable foods, snacks), human contact (petting, massage, laying in lap), climbing, digging up things, lounging in sunlight, and enjoyable sights, sounds, and smells. Because of the individual nature of QOL, the type and quantity of pleasure-eliciting stimuli must be individualized for each animal. Accordingly, the person who is most familiar with the animal’s unique personality and nature is best suited to compile the list of pleasures to be used in the QOL maximization program. It is critically important to be sure that attempts to offer pleasant activities are suitable for the specific disease or disability. For example, when an animal (or human) is very ill and simply desires rest, trying to provide a lot of social interaction or mental stimulation might be unappreciated and possibly even harmful to the healing process. However, in some cases, activities which elicit unpleasant feelings may be beneficial to QOL, as long as the net effect is to tip the QOL scales toward the pleasant side. For example, if going on walks leads a dog to feel some discomfort of arthritis, but the walks are highly pleasurable and desired, then continuing the walks would be expected to result in a net improvement to QOL.

Conclusion

The paramount objective in veterinary care is to maximize QOL. This goal is accomplished, in both ill and healthy animals, by the dual effort of minimizing unpleasant feelings and promoting pleasurable feelings. This keeps the QOL scales tipped as far toward the pleasant side as possible, giving the animal the greatest possible emotional pleasantness in life. By expanding medicine’s focus to include the promotion of pleasant feelings in addition to the traditional medical objective of treating disease, the veterinary clinician’s ability to improve QOL in ill animals is greatly enhanced. Moreover, by including all aspects of life as contributors to an animal’s QOL—not just those directly related to the medical disorder—the ability for us to enhance QOL increases. Lastly, by including mental health and well-being in our calculation of QOL, we can expand and enhance even further our ability to maximize the animal’s QOL. Pet owners and veterinarians should work as a team to improve each animal’s QOL, paying attention to the individual nature of every animal. As research continues to elucidate the emotions, feelings, and diseases of animals, our ability to assess and maximize QOL will steadily improve. As it does, the potential for animals with medical disorders to lead the most enjoyable lives will be greatly enhanced.

References

References are available from author on request.