Rumination—relationship with negative mood and sleep quality
Introduction
Rumination has been defined as “passively and repetitively focusing on one's symptoms of distress and the circumstances surrounding those symptoms” (Nolen-Hoeksema, McBride, & Larson, 1997). However, Martin and Tesser (1996) have suggested a more broad definition of rumination as repetitive thoughts arising without direct cuing in response to an interruption of subjective goals. Considering that ruminators report believing that rumination may help give insight and solve problems (Watkins & Baracaia, 2001) and self-reported ruminative thoughts encompass personal problems (Lyubomirsky, Tucker, Caldwell, & Berg, 1999), the strong focus on symptoms of distress might not be representative of ruminative thoughts in general. Thus rumination could be conceived as repetitive thoughts focusing on problematic situations or events as well as the emotions and symptoms these evoke and the possible consequences.
Rumination has often been investigated in relation to depressive mood, and results from several studies have indicated that rumination may influence the severity and durability of depressed mood (Morrow, 1991, Neddles, 1993, Nolen-Hoeksema et al., 1993). Rumination has thus been shown to predict the severity and durability of depressed mood in recently bereaved adults (Nolen-Hoeksema et al., 1994, Nolen-Hoeksema et al., 1997) and the number of depressive symptoms in response to an earthquake (Nolen-Hoeksema & Morrow, 1991). Rumination may also be related to other negative emotions, e.g. anxiety (Blagden and Craske, 1996, Davey, 1995, Mellings and Alden, 2000, Nolen-Hoeksema, 2000, Roger and Najarian, 1989) and anger (Rusting & Nolen-Hoeksema, 1998) or aggression (Caprara et al., 1987, Roger and Najarian, 1989). This could indicate that rumination is a process which is related to several different negative emotions. One theory, which can account for this, is the associative networks theory according to which “emotions impose a fundamental organizational structure on information stored in semantic network in memory. Each emotion is conceptualised as a central organizing node that links together causally related information” (Rusting & Nolen-Hoeksema, 1998). When an emotion is evoked, associated information will be activated and thus prolong or amplify the emotion. However, associative networks theory could suggest several pathways between rumination and negative mood.
- 1.
First, rumination could be expected to enhance spreading of activation in each different emotional node, thus increasing the emotion irrespective of which node is activated. Most other studies implicitly embrace this possibility since the interrelationship between different negative emotions is seldom addressed.
- 2.
A second possibility is that rumination affects a general “negative emotional node”. Studies often find correlations between different negative emotions like depression, anger and anxiety, and it is not clear from previous studies whether rumination is related to a common component of negative emotions or if it is related to specific components of each negative emotion.
- 3.
A third possibility is that rumination is only associated with one of these negative emotions, for example depression, and the relation between rumination and anger and anxiety can be explained by their relation to depression. Thus rumination activates only one of the emotional nodes and this activation then spreads to related emotional nodes.
Each of these different possibilities can be accommodated by the associative network theory. However, it is important both in order to investigate emotional organisation in memory as well as to illuminate the processes through which rumination influences emotions to investigate the relationship between rumination and several negative emotions simultaneously. As far as we know, the more complex interaction between rumination and depressive, angry and anxious mood has not been explicitly addressed in any previous studies, although many other studies have found relationships between each or several of the negative moods and rumination. In this study, we therefore investigated whether rumination is related to a common negative emotion component or to specific components of angry, anxious and depressive mood.
Different negative emotions have been related to sleep problems or insomnia (Borkovec, 1982), most often anxious and depressive emotions (Borkovec, 1982). At the same time, several authors have emphasized somatic and especially cognitive arousal as possible explanations of some types of insomnia (Borkovec, 1982, Lundh and Broman, 2000, Lichstein and Rosenthal, 1980, Nicassio et al., 1985). Cognitive arousal is often conceptualised as worry and/or repetitive thoughts (Harvey, 2000, Lichstein and Rosenthal, 1980, Lundh and Broman, 2000, Nicassio et al., 1985). Worry is a concept similar to rumination. Agreement on the exact relationship between the two constructs has so far not been reached, but it has been suggested that worry might best be conceptualised as emphasizing future concerns and uncertainty whereas rumination might be conceptualised as emphasizing past failures and certain losses (Segerstrom, Tsao, Alden, & Craske, 2000). Also worry is often highlighted as a central component of anxiety whereas rumination is more often related to depression (Segerstrom et al., 2000). However, the two concepts clearly overlap and have been found to share a common variance of “repetitive thoughts” (Segerstrom et al., 2000). Several types of studies suggest a relationship between worry and sleep quality. Insomniacs often report pre-sleep worries to be the most important reason for not being able to fall asleep (Harvey, 2000, Lichstein and Rosenthal, 1980, Nicassio et al., 1985), and experimental studies have found that increasing cognitive arousal before sleep led to longer sleep latency (Gross & Borkovec, 1982). Only few studies have investigated the relationship between rumination and disturbed sleep. It was found in two studies that subjects suffering from insomnia or psychiatric patients showing poor sleep quality were characterized by rumination and depressive traits, both measured by the MMPI (Bertelson and Monroe, 1979, Kales et al., 1983).
Although rumination and worry are probably related constructs, most research on cognitive arousal and sleep quality focuses on worry as a measure of cognitive arousal, and the two studies that are concerned with rumination and sleep quality present rumination as part of a more broad “depression syndrome”. Thus rumination has not been investigated separately in relation to sleep quality. Rumination is related to several negative emotions like depression, anxiety and anger, and emotional, cognitive and somatic arousal have been argued to be interrelated and unlikely to occur in isolation (Lundh & Broman, 2000). However, whereas several studies have investigated both cognitive and somatic arousal (Broman and Hetta, 1994, Lichstein and Rosenthal, 1980, Nicassio et al., 1985), there is a lack of studies attempting to illuminate the separate contributions of cognitive and emotional factors on sleep. Thus it is difficult to know whether emotional and cognitive arousal contributes separately or in interaction to sleep problems and insomnia, or whether one of the two is more important. Also most of the studies conducted in this area include insomniacs as subjects. While such studies of course are of considerable clinical interest, it is of theoretical interest to investigate if the relationship between sleep, emotion and cognitive arousal is also present for healthy subjects, since this would suggest a continuous relationship between emotion, cognitive arousal and sleep.
The purpose of the present study was therefore to investigate the relationship between rumination, negative mood and sleep quality in a healthy population, thus illuminating possible independent and continuous influences of cognitive arousal, measured as rumination, on subjective sleep quality.
Section snippets
Subjects
The subjects included in this study were 126 young adults (76 females and 50 males) with a mean age of 23.32 years (S.D. 3.40, range 19–40), who were recruited from two university faculties.
Materials and procedure
Rumination was measured using the Rehearsal scale of the Emotional Control Questionnaire (ECQ-R, Roger & Najarian, 1989), where the yes/no format was substituted with a five-point Likert scale, with response format ranging from “doesn't fit at all” (scored as 0) to “fits perfectly” (scored as 4). This was
Rumination and mood
To test the relation between rumination and the negative moods (depressive, anxious and angry mood), the associations between the moods were firstly investigated by calculating a Spearman's rho on the non-transformed mood scores. The correlations ranged from 0.36 to 0.48, illustrating the interrelationship between the three negative moods. In order to investigate the relationship between rumination and the three negative moods, the correlation between rumination and each of the moods was first
Rumination and mood
Our results showed rumination to be related to all of the negative moods and independently associated with depressive and angry mood. Rumination, however, was not significantly related to anxious mood after controlling for angry and depressive mood. This suggests that rumination may be specifically related to angry and depressive mood and not just a common component of negative affectivity. Thus rumination seems to amplify activation selectively in the emotional nodes centred on sadness and
Acknowledgments
The present study was supported by a grant (no. 5028–00–0009) from the Health Promotion and Prevention Research Programme administered by the Danish Research Agency.
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