An Alternative Theory of Generalized Anxiety Disorder
People with GAD worry a lot. But what do they actually fear?
Posted Dec 28, 2020
Generalized anxiety disorder (GAD) is a psychological disorder marked by chronic, pervasive, free-floating worry. The lifetime prevalence of GAD is estimated to be 4 to 6 percent. The disorder is highly comorbid with other anxiety and mood disorders, and it predicts many negative health outcomes, including heart disease, sleep problems, and higher overall mortality rates. GAD is diagnosed in women at twice the rate of men and is the most commonly seen anxiety disorder in primary care.
Worry, defined as repetitive thoughts about negative future events, is a part of life. At the right dose, it can be adaptive, helping direct our attention and improve our preparation in the face of potential threats. People with GAD, however, experience an extreme, chronic, and unrelenting worry that they feel unable to control. Worry no longer works for them but rather enslaves them. People with GAD tend to overestimate the likelihood of negative consequences and predict that the consequences will be catastrophic. Their worries metastasize to involve all areas of everyday life, including health, family, relationships, occupational status, and finances.
Worrying is an effortful cognitive process deployed to prevent or prepare for adverse events. Alas, the chronic worry of GAD is in itself an adversity. For people with GAD, the constant preoccupation with possible future calamities constitutes an ongoing present calamity.
GAD is a debilitating and socially consequential disorder, yet our understanding of it is far from complete. Several theories have attempted over the past few decades to explain the mechanisms underlying GAD. Early theorizing, led by the work of Penn State University psychologist Thomas Borkovec, was premised on the notion that constant worry is an avoidance mechanism, whereby the cognitive preoccupation with negative outcomes serves to protect individuals from experiencing negative emotions. Thinking negative thoughts, in other words, was seen as a way to avoid feeling negative feelings.
This view emerged mainly from research showing that worrying (as opposed to relaxing) right before exposure to a fear-inducing image reduces the somatic response to the image. Worriers’ low reactivity during exposure to feared stimuli was viewed as evidence of a failure of emotional processing, which in turn prevented fear extinction.
This cognitive avoidance model, therefore, argues that "worry has a verbal-linguistic nature and acts as an avoidance strategy to inhibit clear mental images and associated somatic and emotional activation... The inhibition of somatic responses and mental images prevents the emotional processing of fear, and thus prolongs worry.”
In other words, we know that fears can be overcome when fully faced (through the processes of habituation and inhibitory learning). Worry prevents individuals from fully facing their fears. Thus, it rewards the worrier in the short term by reducing their negative reaction to feared stimuli. Yet the failure to fully face fear prevents its elimination. The result is that the worry strategy is embraced while fear remains active, producing more worry.
This process is conceptually analogous to the process of addiction, by which substance use reduces immediate discomfort by preventing the user from fully facing and actually solving their emotionally stressful circumstances. Over time, the substance use itself becomes a bigger problem than whatever problem it was initially used to avoid.
However, more recently, data have been accumulating to suggest that while the experience of worrying predicts a reduced response to subsequent aversive stimuli, it actually produces heightened real-time negative emotion in people with GAD. In other words, rather than allowing for avoidance of negative emotionality, worry in fact induces a negative emotional state. Worriers’ emotional reactions to feared stimuli appear inhibited because worrying has created a higher arousal baseline. If I’m already activated by worry, then presenting a feared stimulus will only add so much to my already high activation.
Considering this evidence, the psychologists Michelle Newman of Penn State and Sandra Llera of Towson University proposed a novel explanation for GAD. According to their Contrast Avoidance Model (CAM), what worry prevents is not negative emotional arousal per se, but rather sharp negative emotional swings.
Newman and Llera cite early studies showing that we experience a negative emotion as less aversive when it is preceded by another negative emotion and that a positive emotion is heightened following a less positive emotion. The authors propose that worrying sustains negative emotion (and the attendant high arousal) in order to avoid a sharp negative emotional contrast (i.e., a sharp uptick in negative emotion) and increase the probability of a positive contrast (upshift toward positive emotion).
Thus, rather than preventing negative emotion, they suggest, worry in fact “heightens negative emotionality such that no further increases in negative affect or physiological responding are observed in response to fear exposure.” This notion is analogous to the idea that some people adopt consistent pessimism as a way to avoid crushing disappointments.
Worry may reward people with GAD, and hence be maintained, because it prevents sharp increases in negative emotions. It may be further maintained by the fact that negative mood experienced during worry can reinforce the need to worry further, by the hyper-responsive threat detection systems characterizing people diagnosed with GAD, and by learning deficits that predispose people with GAD to interpret ambiguity as a threat, fail to terminate their vigilance, and have a selective attentional bias toward anxiety-related stimuli.
Moreover, despite the fact that chronic worry is stressful, emotionally noxious, and physically taxing, people with GAD tend to hold positive beliefs about worry, viewing it as a useful coping strategy, a means of preparing for trouble, and a motivational force toward self-protection. Commonly, worry thoughts become a protective superstition: Having worried much about catastrophes that failed to materialize, people with GAD come to believe that worrying in fact prevents catastrophes from happening. CAM theory suggests that worry’s role in preventing sharp negative emotional turns may be another, central reason it is embraced and maintained.
Over the past several years, research findings have provided support for this model, demonstrating that, indeed, people with GAD tend to be more sensitive to negative emotional contrasts. One recent study by Newman and colleagues (2019) tracked participants with GAD and controls over eight days, measuring their worry, thought valence (positive or negative), and anxious arousal once per hour, 10 times a day. The researchers found that greater worry duration, negative thought valence, and uncontrollability of one's train of thoughts predicted heightened anxiety—as well as a lower likelihood of a negative emotional contrast and a higher likelihood of a positive emotional contrast one hour later. The findings suggest that, in line with CAM theory, “worry reduces the likelihood of a sharp increase in negative affect and does so by increasing and sustaining anxious activation.”
If the theory is supported further, it may have implications for therapy as well. GAD is difficult to treat successfully, and this may be due in part to our incomplete understanding of the nature of fear in GAD. CAM suggests that a principal fear underlying worry in GAD is of negative emotional contrast. If that's the case, then therapists may usefully look to target specifically clients’ contrast avoidance—for example, by repeatedly following relaxation with negative emotional stimuli or by exposing clients to contrasting pleasant and then unpleasant images in quick succession. Facing the fear of negative contrast experiences directly may help extinguish it, thus releasing clients from GAD's worry trap.
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