Can You Really Worry Yourself Sick?

There’s plenty of evidence for a link between anxiety, stress and physical health, and this link occurs at several levels, where stress can adversely affect immune system function resulting in a greater risk of illness, opportunistic infections such as colds and flu, and prolong recovery from illness and disease. Stress is also implicated in greater risk for somatic complaints, cardiovascular disease, and pain perception. Although there’s still no strong evidence that stress can directly cause cancer, there is growing evidence that stress may be related to a return of cancer after successful treatment as a result of stress hormones reactivating dormant cancer cells[1].

But what about the effect of worrying? We often hear the phrase “worried sick,” but can we literally worry until we’re sick? Well, there’s strong evidence linking together worry with stress and physical illness — particularly given that there is a strong relationship between stress and worrying. For example, much of our modern day worrying involves catastrophizing minor stressors known as "daily hassles." These are defined as the irritating, frustrating, distressing demands that characterize everyday transactions with the environment, and examples include losing things, traffic jams, bad weather, arguments and disappointments (and lack of sleep!)[2]. In a study of the relationship between daily hassles and common cold symptoms in a sample of couples from the Stony Brook area of New York, psychologist Arthur Stone and colleagues found that reporting of daily hassles increased in frequency three to four days before the onset of common cold symptoms[3]. They concluded that the stress of daily hassles may well have precipitated common cold symptoms by compromising immune system levels — a finding that has since been replicated in a number of other studies.

Where does worrying fit into all of this? First, a study we conducted a number of years ago showed there is a very strong correlation between daily hassles and frequency of worrying — something we might expect given that most worriers will often be worrying either about the effects of daily hassles or having to encounter future daily hassles[4]. This suggests a close relationship between stress, daily hassles and worrying, but doesn’t necessarily indicate that worry itself directly affects processes that may be detrimental to our health. For example, the effects of worrying may be indirect — worrying may increase our perception of the severity of daily hassles, and that can trigger stress that in turn releases stress hormones such as cortisol — and this will compromise our immune system if cortisol is released over long periods of time as a result of chronic stress.

Secondly, we know that worrying usually takes place during periods of negative mood, and there is abundant evidence that negative mood results in a lowered immune response to disease and infection[5]. So, worrying may be part of a complex system involving stress and negative affect that compromises immune function and results in physical health problems. Whichever way we try to unravel all these relationships, worry is always in there as one of the culprits — even if at this point we can only show it’s guilt by association.

However, Bart Verkuil and Jos Brosschot at Leiden University in The Netherlands and Julian Thayer at Ohio State University have gone one step further and implicated worry directly in the process by which stress causes physical health problems. They argue that worrying increases the total amount of time that stress has a "wear and tear" effect on the human body, and worry does this quite simply by prolonging the amount of time that you consider a stressor to be stressful[6]. That effectively increases the amount of time that you’re pumping stress hormones such as cortisol into your system and damaging your immune responses.

There are a couple of other examples of how chronic worrying may directly influence physical health. First, Laura Kubzansky and colleagues at the Harvard School of Public Health looked at the relationship between worry and coronary heart disease in a cohort of 1,759 older men that they followed over a 20-year period between 1975 and 1995[7]. They found that a high level of worrying at the outset of the study was a significant predictor of coronary heart disease during that 20-year period, and concluded that chronic worry may directly increase the risk of coronary problems. Similar findings came from a study by Alison Holman and colleagues in which they studied the effects of acute stress caused by the 9/11 terrorist attacks. They found that ongoing worries about terrorism predicted cardiovascular health problems up to two or three years after the original attacks.

Verkuil, Brosschot and Thayer attributed these findings to the fact that perseverative worrying will prolong the potency of a stressor. So, in the case of the 9/11 study, worries about terrorism ensured that the stressful effects of 9/11 continued way beyond that date, putting extended strain on an individual’s immune system and physical health. Taken to its extreme, this view suggests that actually occurring stressors are far less important than what happens subsequently in people’s thoughts. That is, their worrying or rumination about the stressor leads to prolonged physiological stress responses that cause most of the damage to physical health — especially in relation to cardiovascular and endocrine activity[8]. This view is becoming more and more mainstream as accumulating evidence suggests that perseverative negative cognition such as catastrophic worrying has a direct effect on somatic health, affecting cardiovascular, autonomic, and endocrine nervous system activity leading to disease and ill-health. It seems you can indeed be “worried sick”[9].

One implication of this apparent direct role that chronic worry has on physical health is that we should be able to ameliorate the effects of stressors by providing interventions for catastrophic worrying following stressful life experiences. Such interventions would limit the long-term physical health effects of the stressor by preventing chronic worrying from maintaining the cognitive potency of the stressor over time. These interventions for pathological worrying would be relevant following common lifetime stressors such as bereavement, severe illness or medical problems, relationship crises, financial problems or unemployment, etc., or as part of a rapid crisis intervention package following life-threatening traumas of the kind that may trigger posttraumatic stress or acute stress symptoms.

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