Elsevier

Clinical Psychology Review

Volume 33, Issue 8, December 2013, Pages 996-1009
Clinical Psychology Review

Assessing treatments used to reduce rumination and/or worry: A systematic review

https://doi.org/10.1016/j.cpr.2013.08.004Get rights and content

Highlights

  • Systematic review of treatments to reduce rumination and/or worry.

  • Mindfulness and cognitive behavioural interventions reduce rumination and worry.

  • Internet-delivered and face-to-face delivered formats appear useful.

  • Rumination and worry may be underpinned by a similar cognitive process.

  • Priorities for future research are highlighted.

Abstract

Perseverative cognitions such as rumination and worry are key components of mental illnesses such as depression and anxiety. Given the frequent comorbidity of conditions in which rumination and worry are present, it is possible that they are underpinned by the same cognitive process. Furthermore, rumination and worry appear to be part of a causal chain that can lead to long-term health consequences, including cardiovascular disease and other chronic conditions. It is important therefore to understand what interventions may be useful in reducing their incidence. This systematic review aimed to assess treatments used to reduce worry and/or rumination. As we were interested in understanding the current treatment landscape, we limited our search from 2002 to 2012. Nineteen studies were included in the review and were assessed for methodological quality and treatment integrity. Results suggested that mindfulness-based and cognitive behavioural interventions may be effective in the reduction of both rumination and worry; with both Internet-delivered and face-to-face delivered formats useful. More broadly, it appears that treatments in which participants are encouraged to change their thinking style, or to disengage from emotional response to rumination and/or worry (e.g., through mindful techniques), could be helpful. Implications for treatment and avenues for future research are discussed.

Introduction

The aim of this systematic review was to assess treatments used to reduce rumination and/or worry.

There are many definitions of worry and rumination. The most often used definition of worry suggests that it constitutes a chain of thoughts and images that are affectively negative and relatively uncontrollable (Borkovec et al., 1998, Borkovec et al., 1983). Descriptively, worry is dominated by negatively valenced thought activity, most often about negative events we are afraid will occur in the future (Borkovec et al., 1998). However, although worry is often associated with negative effects, it may also have some value. For example, day-to-day worries may function to motivate the individual to deal with a perceived threat that is causing worry (Davey, 1993); and many of these daily worries appear to be related to problem-solving. For example, in a study by Szabo and Lovibond (2002) students were asked to self-monitor and record worry-related thoughts when they worried at least a little. These reported thoughts were then categorised by independent raters and over half of the thoughts involved problem solving; e.g., worrying about how to resolve a dispute with a friend, break up with a respective other, or make a plan for the coming day/s. The other half were more stereotypically worry-related thoughts such as anticipating bad outcomes or self-blame for events or situations that had not turned out as planned. Therefore, worry could be a constructive process (if the process results in a solution to a perceived problem) or a non-constructive process (if not focussed on solving a problem; or if an appropriate solution cannot be arrived at).

When it comes to rumination, there are many different definitions, all of which share the common experience of repetitive, intrusive, negative cognitions (see Papageorgiou & Siegle, 2003). Some of these definitions are narrow. For example, Nolen-Hoeksema's (1991) well-known definition of depressive rumination suggests that the focus ofrumination is on one's own depressive symptoms. Other definitions are very broad. For example, Martin and Tesser (1996), in their self-regulation model of ruminative thought, define rumination in the context of thinking about one's own goals, suggesting that this thinking may occur in the absence of immediate environmental cues. According to Martin and Tesser (1996) there are three mechanisms by which ruminative thinking can be stopped: distraction, disengagement from the goal, and goal attainment.

Recurrent negative thinking or thought is a primary component of mood-related emotional disorders. Research regarding rumination and/or worry has been dominated by clinical/health psychology, with rumination and worry thought to be implicated in the aetiology of a number of psychological disorders, e.g., depression and anxiety (Lyubomirsky et al., 1998, Mellings and Alden, 2000), and associated with increased physical symptom reporting (Hazlett & Haynes, 1992), intrusive off-task thoughts (Sarason, Pierce, & Sarason, 1996), negative self-evaluations, diminished feelings ofcontrol and feelings of helplessness (Lyubomirsky, Kasri, & Zehm, 2003). Furthermore, laboratory studies have shown prolonged physiological arousal and delayed recovery in individuals who ruminate or who are asked to recall stressful events (Glynn et al., 2002, Ironson et al., 1992, Lampert et al., 2000, Roger and Jamieson, 1988).

Barlow and DiNardo (1991) proposed that worry is “fundamentally a presenting characteristic of all anxiety disorders with the possible exception of simple phobia” (p. 115); and worry also occurs frequently in major depression (Chelminski & Zimmerman, 2003). Although studies tend to examine worry in relation to anxiety and rumination in relation to depression, a few studies have looked at the effects of both of these forms of repetitive thinking. For example, Segerstrom, Tsao, Alden, and Craske (2000) examined the effects of these processes concurrently and found that repetitive thought of either kind was related to both anxious and depressed symptoms. More recently, McLaughlin, Borkovec, and Sibrava (2007) induced worry and rumination in a student sample to assess whether or not they affected mood in the same, or different, ways. They found that worry and rumination were associated both with increases in anxiety, depression and negative affect, and with decreases in positive affect. Interestingly, their analysis also indicated that shifting from worry to rumination resulted in decreased anxiety and increased depression; and shifting from rumination to worry created an opposing pattern.

Therefore, when the two forms of thinking occur sequentially, it appears worry is associated with predominantly anxious affect, and rumination is associated with predominantly depressive affect. As such, both processes appear to lead to the generation of negative mood states; with the different outcomes reflective of the focus or content of rumination or worry respectively. These findings are further supported by the results of prior studies conducted separately on worry and rumination. For example, Segerstrom, Stanton, Alden, and Shortridge (2003) found that negative affectivity is generated by negative thinking of any type; Chelminski and Zimmerman (2003) found that worry occurs in depression; and Nolen-Hoeksema (2000) found that rumination predicts the onset of anxiety. These findings suggest a shared component to these forms of repetitive thinking and a considerable research base supports this showing that anxiety and depression are frequently comorbid (Brown and Barlow, 1992, Brown et al., 2001, Kessler et al., 1995, Kessler et al., 1994, Kessler et al., 1998). This comorbidity may be explained in a number of ways: firstly, it is possible that having one disorder increases the risk of developing another; alternatively, it is possible that anxiety and mood disorders may develop from the same underlying predisposition (Barlow, 2002).

In line with the notion that these disorders may develop from the same underlying predisposition, one possibility is that both of these disorders are underpinned by a similar cognitive process. For Brosschot, Gerin, and Thayer (2006) rumination and worry represent different but related manifestations of the same underlying cognitive process. The difference in these constructs is reflected in a different focus of “content” (e.g., future focussed in worry; past focussed in rumination); however, they are purported to share an underlying cognitive process which maintains psychophysiological arousal. This process is labelled ‘perseverative cognition’ and is defined as: “the repeated or chronic activation of the cognitive representation of one or more psychological stressors” (Brosschot et al., 2006, p. 114). Our unique ability as humans means that we can look back and learn from the past, and we can look ahead to plan for the future; however, this may also lead to ‘ruminating’ about the past, or ‘worrying’ about the future (Brosschot, Verkuil, & Thayer, 2010). Whilst psychological stressors themselves do not involve direct physical danger, they are composed of perceived threats to the physical or psychological integrity of the individual (Brosschot et al., 2010). It is these cognitive representations, or thoughts, that result in a “fight-or-flight” response (Frijda, 1988), which is followed by a cascade of biological and physiological changes in the body. These changes begin in the brain and cause peripheral responses to stress such as increased heart rate and blood pressure; and higher levels of stress hormones such as cortisol (Lovallo, 2004).

Evidence in the literature suggests that perseverative cognition (e.g., rumination and worry) in addition to having direct physiological effects, also mediates the prolonged effects of stressors. Some researchers have considered the relationship between rumination/worry and somatic disease or somatic complaints; with suggestive evidence for a prospective relationship. For example, Brosschot and van den Doef (2006) reported that a total of 1 week's worry duration was prospectively related to health complaints in high school and college students. Trait rumination has been prospectively related to self-reported physical health issues one year later (Thomsen et al., 2004); and cross-sectional relationships have been found between trait rumination and health complaints (Lok & Bishop, 1999) and between frequency of worry about conflicting goals and somatisation (Emmons & King, 1988). Furthermore, with regard to verifiable disease outcome, a tendency to worry has been shown to predict a second myocardial infarction (Kubzansky et al., 1997).

Other researchers have considered the relationship between worry/rumination and endocrine, neuroendocrine and physiological responses (e.g. cardiac activity; blood pressure). Chronic activation of the hypothalamic–pituitary–adrenal axis (predominantly cortisol release) is purported to increase an individual's susceptibility to many disease states. This is thought to be due to suppression of the immune system which has multiple pathological effects, e.g., dysregulation of metabolism and hippocampal degeneration (Brosschot et al., 2006). Several studies have shown that rumination and worry are associated with abnormal immune responses and elevated levels of cortisol. For example, trait rumination has been associated with higher morning salivary cortisol (Schlotz, Hellhammer, Schulz, & Stone, 2004); and a higher number of several types of luekocytes (white blood cells of the immune system involved in defending the body against disease; Thomsen et al., 2004). Other studies have reported that participants reporting high levels of trait worry had fewer natural killer (NK) cells (Segerstrom, Solomon, Kemeny, & Fahey, 1998); and that high trait worry was related to suppression of an expected increase in NK cells when exposed to fear-evoking situations (Segerstrom, Glover, Craske, & Fahey, 1999).

People with chronically elevated heart rates (HR), and reduced heart rate variability (HRV; an indicator of parasympathetic activity), are at increased risk for all-cause mortality (Palatini & Julius, 1997); and reduced HRV has also been associated with increased risk of developing hypertension and other cardiovascular disorders (Stein and Kleiger, 1999, Thayer and Friedman, 2004). A sustained level of high blood pressure (BP) is also a risk factor for many diseases including cardiovascular disease (CVD) and diabetes (Schwartz et al., 2003). Researchers have shown that both dispositional measures of, and experimentally induced, worry are associated with low HRV and high HR (Lyonfields et al., 1995, Thayer et al., 1996). Furthermore, trait rumination has been associated with slower HR recovery after cognitive stress tasks (Roger & Jamieson, 1988); and state, but not trait, worry has been related to high HR (Dua & King, 1987). Elevated BP has also been associated with anticipation before emotional events in several studies; e.g., in students anticipating oral defence of their PhD (van Doornen & van Blokland, 1992), prior to dental treatment (Brand, Gortzak, Palmer-Bovba, Abraham, & Abraham-Inpijn, 1995), and mental arithmetic (Contrada, Wright, & Glass, 1984). In addition, multiple studies showed that emotional reactivity (which is strongly related to worry and rumination) was positively related to resting BP (Melamed, 1987), ambulatory BP (Melamed, 1996), and to high risk levels of lipids (fats) in blood plasma (Melamed, 1994).

Taken together, these findings appear to suggest that perseverative cognition (e.g., rumination, worry) is associated with decreased parasympathetic activity and increased sympathetic nervous system activity (Brosschot et al., 2006). Decreased parasympathetic activity suggests that rumination and worry are likely independent risk factors for CVD; furthermore, low parasympathetic activity has also been found to characterise depression and anxiety disorders (Friedman and Thayer, 1998, Friedman et al., 1993, Lyonfields et al., 1995, Thayer et al., 1996). Interestingly, depression and anxiety are increasingly documented as important risk factors for cardiovascular and other disorders (e.g., Kawachi et al., 1994, Wulsin et al., 1999). Therefore it is possible that worry and rumination may serve as mediators of the relationship between anxiety and depression with CVD (Brosschot et al., 2006).

Another possibility is that anxiety and depression are underpinned by a shared mood trait such as negative affect (McLaughlin et al., 2007). Watson, Clark, and Tellegen (1988) characterise negative affect (NA) as a general dimension of subjective distress and “unpleasurable engagement that subsumes a variety of aversive mood states” (p. 1063); e.g., fear, nervousness, guilt, contempt, anger and disgust. Trait NA has been shown to roughly correspond to the personality factor anxiety/neuroticism; and Tellegen has also suggested that high levels of NA (both state and trait) are major distinguishing features of depression and anxiety, respectively (Tellegen, 1985). McLaughlin et al. (2007) suggest that this is the shared underlying factor which fosters rumination and/or worry. The positions of Brosschot et al. (2006) and McLaughlin et al. (2007) are compatible in as much as a predisposition to engage in perseverative cognition with a negative focus may potentially be causal in the development of anxiety and/or depression. Worry and rumination appear to worsen, not resolve, negative emotional states (Morrow and Nolen-Hoeksema, 1990, Nolen-Hoeksema and Morrow, 1993); furthermore, both forms of perseverative cognition are associated with over-general memory and a high level of abstract as opposed to concrete processing (e.g., Watkins and Teasdale, 2001, Williams, 1996).

In a comprehensive review, Brosschot et al. (2006) suggested that perseverative cognition (e.g., rumination, worry) may be part of a causal chain that can lead to long-term health consequences, including cardiovascular disease and other chronic conditions and illnesses. A position that appears to be supported by the research presented above. Given the prevalence of perseverative cognition (e.g., rumination, worry) in the aetiology of different illnesses and conditions, it is important to understand what interventions may be useful in reducing the incidence of rumination and/or worry.

The objective of this systematic review was to assess treatments used to reduce rumination and/or worry.

An initial review of the literature highlighted that there were very few studies explicitly designed to target rumination or worry. Therefore we expanded our inclusion criteria such that studies had to either: 1. explicitly treat rumination/worry; or 2. include secondary measures for the effects of treatment on rumination/worry. Studies in which rumination or worry was measured, but where they were only tested as mediators/moderators for changes in other study variables, were not included. The following study designs were eligible for inclusion: randomised controlled trials (RCTs); randomised clinical controlled trials; clinical controlled trials; waitlist controlled trials; randomised trials; cohort studies; quasi-experimental studies.

Only articles from peer reviewed journals (January, 2002–December, 2012) and written in English were eligible for inclusion. We limited our search to research published from 2002 to 2012 because we were interested in understanding the current landscape with regard to treatments utilised in the reduction of rumination and/or worry.

This review considered studies of adults (> 18 years of age) only. We included studies where participants were drawn from both clinical and non-clinical (e.g., general population, students) populations. Studies including participants with depression, anxiety (or a specific anxiety disorder, e.g., social phobia, generalised anxiety disorder, etc.) or a mixture of depression and anxiety were eligible for inclusion in the review. Studies including participants with learning disabilities or severe mental disorder (e.g., schizophrenia, bipolar disorder, depression with psychotic symptoms, psychosis, serious suicidal thoughts) or alcohol or substance abuse were not eligible for inclusion.

Studies were eligible for inclusion if they utilised primary or secondary measures for rumination and/or worry: e.g., Ruminative Response Scale (RRS; Nolen-Hoeksema, 1991), or equivalent; Penn State Worry Questionnaire (PSWQ; Meyer, Miller, Metzger, & Borkovec, 1990), or equivalent.

The following electronic databases were examined in December, 2012: PsycINFO; PsycARTICLES; Medline; the Cochrane Library database of systematic reviews; and the Centre for Reviews and Dissemination (CRD) database.

The search in PsycINFO, PsycARTICLES and Medline made use of the following search terms: 1 Rumination; 2 Ruminat* AND thought(s) OR thinking; 3 Perseverative AND thought(s) OR thinking; 4 Repetitive AND thought(s) OR thinking; 5 Intrusive AND thought(s) OR thinking; 6 Negative AND thought(s) OR thinking; 7 Worry; 8 Worry AND thought(s) or thinking; 9 Anxi*; 10 Anxi* AND thought(s) OR thinking; 11 Stress AND thought(s) OR thinking; 12 Depress* AND thought(s) OR thinking; 13 #1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7 OR #8 OR #9 OR #10 OR #11 OR #12 AND “intervention” OR “randomis(z)ed controlled trial” OR “RCT” OR “Controlled trial” OR “Waitlist controlled trial” OR “Randomis(z)ed trial” OR “Cohort” OR “Quasi-experimental”. The search in CRD and Cochrane Library databases made use of the following terms: 1 Rumination; 2 Perseverative AND thought(s) OR thinking; 3 Repetitive AND thought(s) OR thinking; 4 Intrusive AND thought(s) OR thinking; 5 Negative AND automatic thought(s) OR thinking; 6 Worry; 7 Stress; 8 Depression AND thought(s) OR thinking.

Brackets indicate where search terms were entered twice with the different spellings. Search terms were selected based on common key terms identified during an initial search of the literature and related reviews.

Section snippets

Methods

The authors screened abstracts and titles of articles against the inclusion criteria and full text versions of potentially relevant articles were obtained for more detailed analysis. In total, 108 articles were obtained and reviewed. Of these, 89 were excluded from this review for the following reasons: not an intervention study, no measure of rumination or worry (or rumination/worry measured but direct effects not reported), sample not adults, participants inappropriate, duplicate data

Medthodological quality and treatment integrity

We scored studies for methodological quality according to criteria developed by Jadad et al. (1996); and for treatment integrity against items from Foa & Meadow's “gold standards” for treatment outcome studies (Foa & Meadows, 1997). The 19 studies included in this review were assessed by both authors separately; and then together. Any disagreements were resolved by discussion between the authors.

Results

The following results represent a narrative synthesis of all included studies. Given the heterogeneous nature of the studies included in this review (e.g., participants drawn from different populations and varied interventions delivered in different formats) it was not appropriate or feasible to conduct a meta-analysis. Petticrew and Gilbody (2004) suggest that studies with the best methodological quality should contribute more to the results of systematic reviews and this is the approach we

Discussion

This systematic review aimed to assess treatments utilised for the reduction of rumination and/or worry. Most of the studies included in the review evidenced fair to excellent methodological quality and treatment integrity. Nevertheless, there were a few studies for which we suggest results should be viewed with caution, predominantly due to the quality of statistical analysis. Robins et al. (2010) and Westra et al. (2009) did not conduct ITT analysis, choosing only to report findings from

Conclusions

This systematic review suggests that mindfulness-based and cognitive behavioural interventions may be effective in the reduction of both rumination and worry. Irrespective of delivery mode, both Internet-delivered and face-to-face delivered formats appear to be useful. More broadly, treatments in which participants are encouraged to change their thinking style, or to disengage from their emotional response to rumination and/or worry (e.g., through mindful techniques), could be helpful.

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