DEPRESSIVE RUMINATION AND PAST DEPRESSION IN JAPANESE UNIVERSITY STUDENTS: COMPARISON OF BROODING AND REFLECTION 1, 2

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1 Psychological Reports: Disability & Trauma 2014, 114, 3, Psychological Reports 2014 DEPRESSIVE RUMINATION AND PAST DEPRESSION IN JAPANESE UNIVERSITY STUDENTS: COMPARISON OF BROODING AND REFLECTION 1, 2 AKIRA HASEGAWA Faculty of Human Relations Tokai Gakuin University, Japan YOSUKE HATTORI Graduate School of Arts and Sciences The University of Tokyo, Japan MUNENAGA KODA Graduate School of Medicine University of the Ryukyus, Japan TSUYOSHI KONDO Graduate School of Medicine University of the Ryukyus, Japan JUN KAWAGUCHI Department of Psychology, Nagoya University, Japan Summary. The Ruminative Responses Scale, a measure of depressive rumination, contains two subscales: Brooding and Reflection. Treynor, Gonzalez, and Nolen- Hoeksema (2003) proposed that Brooding is maladaptive and Reflection is adaptive. This article examined the relationships among Brooding, Reflection, and previous depression in two samples of Japanese undergraduates, who were non-depressed at the time of their participation. Based on answers to a self-report measure, participants were divided into a formerly depressed group, who had experienced an episode that met the criteria for major depression, and a never-depressed group. Logistic regression analyses were conducted with Brooding, Reflection, and current depression as the independent variables and past depression as the dependent variable. Brooding had consistent positive associations with past depression. The relationship between Reflection and past depression was not significant for one sample, but was statistically significant and positive in the second sample. In the second sample, Brooding and Reflection both were related with past depression after controlling for worry. The Ruminative Responses Scale (RRS; Nolen-Hoeksema & Morrow, 1991 ) is a measure of depressive rumination, which is defined as repetitive and passive thinking about one's symptoms of depression and the possible causes and consequences of these symptoms ( Nolen-Hoeksema, 2004 ). Consistent with the Response Styles Theory ( Nolen-Hoeksema, 1991 ; Nolen-Hoeksema, Wisco, & Lyubomirsky, 2008 ), groups with current or remitted Major Depressive Disorder score higher on the RRS relative to never-depressed groups ( Joormann, Dkane, & Gotlib, 2006 ; Beevers, Rohde, 1 Address correspondence concerning this article to Akira Hasegawa, Tokai Gakuin University, East Campus 360, 5-68 Naka-kirino, Kakamigahara City, Gifu, , Japan or (mail-ad.of.hasse@tokaigakuin-u.ac.jp ). 2 The authors thank Hideki Ohira, Takuya Yoshida, Takashi Furusato, and Koji Tsuchiya for their help with data collection. DOI /15.03.PR0.114k26w6 ISSN

2 654 A. HASEGAWA, ET AL. Stice, & Nolen-Hoeksema, 2007 ; McMurrich & Johnson, 2008 ). Numerous studies have shown that higher scores on the RRS are predictive of the level of depression ( Butler & Nolen-Hoeksema, 1994 ; Just & Alloy, 1997 ), as well as the onset and relapse of major depressive episode after controlling for baseline depression level ( Nolen-Hoeksema, 2000 ; Spasojevic & Alloy, 2001 ; Michalak, Holz, & Teismann, 2011 ). 3 Consistent with these findings, many experimental studies have shown that rumination increases depression. For example, negative mood increased in depressed participants who were asked to focus on the meanings, causes, and consequences of their current feelings for 8 min. (i.e., induced to ruminate), whereas participants with the identical mood status who were induced to distract from negative thoughts or feelings for 8 min. had improved mood ( Nolen-Hoeksema & Morrow, 1993 ). This finding indicated that thinking about one's depressed mood (i.e., depressive rumination) exacerbated the depressed mood. Induced rumination is considered to lead to various outcomes, such as impaired social-problem solving ( Lyubomirsky & Nolen-Hoeksema, 1995 ; Lyubomirsky, Tucker, Caldwell, & Berg, 1999 ; Donaldson & Lam, 2004 ), negative interpretations about oneself, one's situation, and future events ( Lyubomirsky & Nolen-Hoeksema, 1995 ; Lyubomirsky, et al., 1999 ; Lavender & Watkins, 2004 ), frequent retrieval of negative autobiographical memories and increased memory-related distress ( Lyubomirsky, Caldwell, & Nolen-Hoeksema, 1998 ; Williams & Moulds, 2010 ), overgeneral autobiographical memories ( Park, Goodyer, & Teasdale, 2004 ; Sutherland & Bryant, 2007 ), and deficits in cognitive control ( Watkins & Brown, 2002 ; Philippot & Brutoux, 2008 ; Whitmer & Gotlib, 2012 ). These findings suggest that depressive rumination is a vulnerability factor for depression and one of the core cognitive processes in the pathology of depressive disorders. Although several versions of the RRS, differing in item composition, have been proposed, most recent studies have used the version of the RRS revised by Treynor, et al. (2003 ), which comprises 22 standard items. Because Treynor, et al. (2003 ) suggested that 12 items of the RRS could be confounded with depressive symptoms, these items were considered unsuitable for investigating the relationship between rumination and depression. The remaining 10 items were subjected to an exploratory factor analysis, which yielded two factors: Brooding, i.e., a passive comparison of one's current situation with some unachieved standard and Reflec- 3 As described below, it is possible that some items of the RRS could be confounded with depressive symptoms. However, the finding that the formerly depressed groups scored higher on the RRS than the never-depressed groups and that the RRS score predicted future depression levels, even after controlling for baseline depression, is suggestive that rumination is not merely a depressive symptom but a vulnerability factor for depression.

3 DEPRESSIVE RUMINATION AND PAST DEPRESSION 655 tive pondering or Reflection, i.e., a purposeful turning inward to engage in cognitive problem solving to alleviate one's depressive symptoms (Treynor, et al., 2003, p. 256). This two-factor structure of the RRS has been supported by other studies (e.g., Schoofs, Hermans, & Raes, 2010 ). These two factors appear to be distinct subcomponents, since Brooding and Reflection have different predictiveness for depression. Treynor, et al. (2003 ) conducted a longitudinal study over one year with a community sample. A multiple regression analysis was conducted with Brooding, Reflection, and depression level at baseline as the independent variables and depression level at one-year follow-up as a dependent variable. They demonstrated that while Brooding was associated with more depression at follow-up, Reflection was associated with less depression. This pattern, as noted by the authors, suggests that Brooding may represent a maladaptive aspect of rumination and Reflection may represent an adaptive aspect. Treynor, et al. (2003 ) suggested that Reflection may eventually be adaptive in reducing negative affect, perhaps because it leads to effective problem solving (p. 257). In line with this suggestion, Marroquin, Fontes, Scilletta, and Miranda (2010 ) showed that Reflection, in contrast to Brooding, was correlated strongly with active coping and correlated weakly with passive coping. Also, Brooding is generally related to pathological cognitive processes (e.g., attentional bias, overgeneral autobiographical memory, and concern over mistakes in perfectionism), whereas Reflection typically is not (e.g., Joormann, et al., 2006 ; Harris, Pepper, & Maack, 2008 ; Debeer, Hermans, & Raes, 2009 ). These findings indicate that Brooding and Reflection assess related, but relatively distinct, subcomponents of depressive rumination. Previous studies using the RRS compared scores for Brooding and Reflection between formerly depressed groups of people whose symptoms met diagnostic criteria for major depressive episodes and groups of people who were never clinically depressed. One of the vulnerability markers of depression is previous experience of a major depressive episode. For example, Kendler, Thornton, and Gardner (2000 ) showed that the more depressive episodes people have experienced, higher is the possibility that they will experience future major depressive episodes. One method to specify the psychological vulnerability factor for onset and relapse of major depressive episodes is to compare the psychological characteristics of formerly depressed groups and never-depressed groups. The two groups may differ in terms of depression histories, suggesting that it might be a risk marker for future onset of major depressive episodes but not for current depression. Therefore, the psychological characteristics of formerly depressed groups may not be a contaminant of depression but a vulnerability factor for relapse. Interestingly, although the total RRS score of the groups with major depression in remission was higher than in the non-

4 656 A. HASEGAWA, ET AL. depressed groups ( Joormann, et al., 2006 ; Beevers, et al., 2007 ; McMurrich & Johnson, 2008 ), and the total RRS score predicted future major depressive episodes ( Nolen-Hoeksema, 2000 ; Spasojevic & Alloy, 2001; Michalak, et al., 2011 ), the total RRS score of the participants who experienced major depressive episodes was not significantly different between before and after the episodes ( Beevers, et al., 2007 ). 4 These findings suggest the possibility that some psychological characteristic of formerly depressed groups might be the cause of prior episodes, as well as a cause for future onset of major depressive episodes (although other interpretations are also possible). Teasdale (1988 ) proposed that one difference between people who are vulnerable for major depressive episodes and those who are not vulnerable are cognitive processes activated during mild dysphoria. In the non-depressed phase, when vulnerable people experience mild dysphoria the mood activates cognitive processes that perpetuate their depression, which leads to a self-perpetuating, cognitive-affective vicious cycle. Depressive rumination appears to be one such cognitive process ( Teasdale, 1988 ). 5 Several studies have indicated that Brooding is related to past major depressive episodes, but studies of the relationships between Reflection and past depression showed mixed results. Joormann, et al. (2006 ) showed that groups with Major Depressive Disorder in remission scored higher on Brooding relative to never-depressed groups, but did not score higher on Reflection. Consistent with this finding, Sanders and Lam (2010 ) showed that a group with Major Depressive Disorder in remission scored higher only on Brooding relative to a never-depressed group. However, other studies ( Watkins & Moulds, 2009 ; Joormann & Gotlib, 2010 ) showed that groups with Major Depressive Disorder in remission scored higher than never-depressed groups both on Brooding and Reflection. These mixed results may be due to the different characteristics of the sample (e.g., age, sex ratios, depression status, or comorbidity), the moderate reliability of Reflection, or some moderator variables. Hasegawa (2013 ) developed the Japanese version of the RRS based upon the item composition of Treynor, et al. (2003 ), and confirmed the construct validity and reliability of this measure. This study also found that Brooding was correlated more strongly with the current depression score 4Beevers, et al. (2007 ) utilized a shorter version of the RRS, which was composed of six items; therefore, they did not examine whether Brooding and Reflection subscale scores differed before and after the episodes. 5 The origins of individual differences in ruminative tendencies have been proposed, which could be genetic factors and environmental factors, such as sexual and emotional abuse in childhood, over-controlling parenting, and the experiences of major depressive episodes resulting from reasons other than rumination (see Teasdale, 1988 ; Nolen-Hoeksema & Watkins, 2011 ).

5 DEPRESSIVE RUMINATION AND PAST DEPRESSION 657 ( r =.55), assessed with the Center for Epidemiologic Studies Depression Scale (CES D; Radloff, 1977 ), than was Reflection ( r =.36). These results are consistent with numerous studies which showed that Brooding was related more strongly with current depression than was Reflection (e.g., Treynor, et al., 2003 ; Schoofs, et al., 2010 ). However, Hasegawa's (2013 ) report did not consider whether scores on the Brooding and Reflection of the Japanese RRS differ between the formerly depressed groups and never-depressed groups. Considering that the RRS has been utilized globally in research and clinical practice on depression, information about whether the Japanese RRS has similar psychometric properties as other language versions contributes to further research on depression, as well as to clinical practice in Japan. The present study examined whether Brooding and Reflection are related with previous depression that met the criteria for major depression in two samples of Japanese undergraduates, who were non-depressed at the time of their participation. Participants were divided into a formerly depressed group and a never-depressed group based on self-report measures. 6 The current depression level was assessed with the CES D and past depression status was identified with the Inventory to Diagnose Depression, Lifetime Version (IDDL; Zimmerman & Coryell, 1987 ). Episodes are identified with the IDDL as depressive episodes rather than as major depressive episodes because of the controversy concerning whether selfreport instruments can validly diagnose major depression particularly in a nonclinical college sample (see Roberts, Gilboa, & Gotlib, 1998 ). It was predicted that the formerly depressed group would score higher on the Brooding subscale of the Japanese RRS than individuals who were never depressed, because such findings are obtained consistently in previous studies ( Joormann, et al., 2006 ; Watkins & Moulds, 2009 ; Joormann & Gotlib, 2010 ; Sanders & Lam, 2010 ). On the other hand, previous studies showed mixed findings about the relationship between Reflection and previous depression. Reflection is related more weakly to pathological cognitive and behavioral factors than Brooding (e.g., Joormann, et al., 2006 ; Harris, et al., 2008 ; Debeer, et al., 2009 ; Marroquin, et al., 2010 ), so it was expected that only Brooding would be related to previous experiences of depressive episodes, or at least Reflection would be related less strongly with those experiences than Brooding. One issue that previous 6 One of the purposes of this study was to replicate the findings regarding the association between RRS subscales and past major depression obtained in previous studies. Therefore, participants were divided into two groups based on DSM IV criteria. Previous studies have examined the relationships between RRS subscale scores and the experiences of major depressive episodes, but not the severity of depressive symptoms experienced in the worst lifetime episodes.

6 658 A. HASEGAWA, ET AL. studies were not able to consider was the correlation between Brooding and Reflection. Treynor, et al. (2003 ) showed that the correlations between the variables were.37 and.42 for Times 1 and 2, respectively. These correlations indicated that individuals who persisted in brooding rumination would have a tendency to initiate reflective rumination and vice versa. Considering these findings, the observed relationships between Reflection and past major depressive episode may be due to the moderate intercorrelations between Brooding and Reflection. Reflection would appear to be associated with previous depression, although in fact only Brooding but not Reflection was associated directly with previous depression. To confirm that Brooding, but not Reflection, is a vulnerability factor for depression, the associations between the RRS subscales and past depression should be examined after controlling for each RRS subscale. This examination leads to consideration about whether Reflection represents an adaptive aspect of rumination or maladaptive one. In addition, in Study 2, worry proneness was assessed to examine partial relationships among Brooding, Reflection, and previous depression after controlling for worry. Worry is defined as a chain of thoughts and images, negatively affect-laden and relatively uncontrollable. The worry process represents an attempt to engage in mental problem-solving on an issue whose outcome is uncertain but contains the possibility of one or more negative outcomes ( Borkovec, Robinson, Pruzinsky, & Depree, 1983, p. 10), and is considered to be a primary attribute of Generalized Anxiety Disorder. Depressive rumination and worry share some characteristics (e.g., negative content and perseverative style) but have distinct aspects (e.g., depressive rumination is focused on past events, while worry is focused on future events; Watkins, Moulds, & Mackintosh, 2005 ). Some researchers suggested that depressive rumination is a vulnerability factor for depression and worry is a central cognitive process of anxiety disorders, especially Generalized Anxiety Disorder (e.g., Nolen-Hoeksema, et al., 2008 ). In order to examine this suggestion, a questionnaire study that simultaneously utilized the RRS and the Penn State Worry Questionnaire (PSWQ; Meyer, Miller, Metzger, & Borkovec, 1990) was conducted. A joint exploratory factor analysis indicated that RRS and the PSWQ items were composed of separate factors ( Fresco, Frankel, Mennin, Turk, & Heimberg, 2002 ; Goring & Papageorgiou, 2008 ), suggesting that these two constructs are distinct (although three RRS items loaded on a factor that mainly composed of the PSWQ items; Goring & Papageorgiou, 2008 ). However, total RRS and PSWQ scores were similarly related to depression and anxiety ( Segerstrom, Tsao, Alden, & Craske, 2000 ; Fresco, et al., 2002 ). Watkins and Moulds (2007, 2009 ) showed that the total RRS and PSWQ scores were higher in groups with current major depression than in never-depressed groups. The group with current major depression had

7 DEPRESSIVE RUMINATION AND PAST DEPRESSION 659 a higher total RRS score than the group with Generalized Anxiety Disorder, but Brooding, Reflection, and PSWQ scores did not differ between the two groups ( Yook, Kim, Suh, & Lee, 2010 ; McEvoy, Watson, Watkins, & Nathan, 2013 ). McEvoy, et al. (2013 ) showed that among participants suffering principally from major depression, the group with comorbid anxiety disorders had higher Brooding and total RRS and PSWQ scores than those with no comorbid anxiety disorders. A few studies have compared a formerly depressed group and a never-depressed group by using PSWQ scores. Watkins and Moulds (2007, 2009 ) showed that a formerly depressed group scored higher on the PSWQ than a never-depressed group. However, this study did not clarify whether depressive rumination and worry were directly related to past depression, or indirectly rerated via other cognitive processes. In Study 2, a logistic regression analysis was conducted with RRS subscales, PSWQ, and current depression as the independent variables and experience of past depression as the dependent variable. If Brooding or Reflection is related to past depression even after controlling for worry, then this study believes that subcomponent of rumination is a vulnerability factor for depressive episode. Study 1 M ETHOD Participants Japanese undergraduate students ( N = 485) took part in this study in five universities: Chubu University, Nagoya University, Nagoya Women's University, Nanzan University, and Tokai Gakuin University. Although exact demographic information was not recorded, the students at these universities are largely native-speaking Japanese. Participants were recruited in their classes, mainly psychology classes. All participants who agreed to take part in this study completed the questionnaires there. Due to practical reasons, random sampling was not conducted in this study. All individuals voluntarily participated in the study, which was approved by the Ethics Committee of Tokai Gakuin University. The purpose of this study was to examine the relationships between the RRS subscales and past depression status in currently non-depressed undergraduate students. Therefore, the data of currently depressed participants who scored more than 16 points on the CES D (the cutoff recommended by Radloff, 1977 ) were eliminated ( n = 250). 7, 8 Next, based on 7 It could be argued that the inclusion of currently depressed participants in the analyses added important information. However, because the cutoff score of the CES D did not assure that participants met current criteria for major depressive episode, it was difficult to interpret the characteristics of the currently depressed group. For this reason, data of this group were eliminated. Hasegawa (2013 ) showed that Brooding and Reflection were correlated with the

8 660 A. HASEGAWA, ET AL. their responses to the IDDL, a formerly depressed group and a never-depressed group were selected from the remaining 235 participants. Participants who had experienced past depressive episode, defined as meeting DSM IV symptom criteria for major depressive episode, were selected as the formerly depressed group. The procedure to identify depression using their responses on the IDDL was based on Sato, Uehara, Sakado, Nishioka, Ozaki, Nakamura, et al. (1997). Formerly depressed individuals (a) scored two or more points on the severity of the depressive mood item (Item 1) or three or more points on the loss of interest or pleasure items (Item 5 or 6), and experienced the symptoms for more than two weeks (identified by the duration response for each item), and (b) experienced at least five symptoms listed in the A criterion for major depressive episode (i.e., scored two or more points on severity for each symptom item and reported experiencing the symptoms for more than two weeks). Participants who had never experienced both depressive mood and loss of interest for two successive weeks were selected into the never-depressed group. The criteria for this group were adopted from Ma and Teasdale (2004). On the IDDL, never-depressed individuals did not score two or more points for severity on the depressive mood item and three or more points for loss of interest items, or if they scored those points they did not experience the symptoms for 2 weeks. The formerly depressed group consisted of 39 participants (11 men, 28 women). The mean age of this group was 20.6 yr. ( SD = 1.8, range = 18 to 26). The never-depressed group consisted of 144 participants (43 men, 100 women; one participant did not report sex and age). The mean age of this group was 19.9 yr. ( SD = 3.70; range = 18 to 59). Measures Inventory to Diagnose Depression, Lifetime Version (IDDL: Zimmerman & Coryell 1987 ). The IDDL is a self-report scale designed to screen for experiences of past major depressive episode. The scale includes 22 items, each rated on a five-point rating scale from 0 to 4 for severity. If the participants rate one or more points for an item, they also rate the duration for the item, such as whether the symptoms persisted for more than two weeks. Uehara, Sato, Sakado, and Sato (1995) translated the IDDL into Japanese. The Japanese version has adequate reliability and validity ( Uehara, et al., 1995 ; Sakado, Sato, Uehara, Sato, & Kameda, 1996 ; Sato, Ue- CES D score, indicating that currently depressed participants scored higher on each RRS subscale (although Brooding was more strongly correlated with current depression than Reflection). 8 The rate of participants in this study that scored more than 16 points on the CES D was similar to the rate that has been previously reported (45%; Santor, Zuroff, Ramsay, Cervantes, & Palacios, 1995 ).

9 DEPRESSIVE RUMINATION AND PAST DEPRESSION 661 hara, Sakado, Sato, Nishioka, & Kasahara, 1996 ). This scale was used to identify participants experiences of past depressive episodes. In addition, the scores for severity of all 22 items were summed as the severity of the worst lifetime episode. Uehara, et al. (1995 ) reported that the mean IDDL severity scores of the formerly depressed patients group and the healthy control group, identified by using a structured clinical interview were 47.1 ( SD = 12.5) and 12.8 ( SD = 8.0), respectively. The internal consistency reliability of severity was.90 in the final sample analyzed in Study 1 ( n = 183). Center for Epidemiologic Studies Depression Scale (CES D; Radloff, 1977 ). The CES D is a self-report scale designed to measure depressive symptomatology in the general population. The scale includes 20 items, each rated on a four-point rating scale with anchors 0: Rarely or none of the time and 3: Most or all of the time. Shima, Shikano, Kitamura, and Asai (1985 ) translated the CES D into Japanese and demonstrated an adequate reliability and validity for the scale. The mean score on the CES D reported by Hasegawa (2013 ) based on research conducted with Japanese undergraduate students was ( SD = 8.19; range = 0 49). The internal consistency reliability of this scale in the sample analyzed in Study 1 ( n = 183) was very low (.42), perhaps because of the small range of the CES D scores (0 15 points for total score). Using the data from the full sample who took part in Study 1 ( N = 485), the internal consistency of the CES D was.88, indicating adequate internal consistency. Ruminative Responses Scale (RRS; Treynor, et al., 2003 ). The RRS includes 22 items, each rated on a four-point rating scale anchored by 1: Almost never and 4: Almost always. The RRS contains 10 items that compose the Brooding and Reflection subscales. Adequate psychometric properties were reported, including good internal consistency, good test-retest reliability, and evidence for construct validity for the total score and subscale scores ( Treynor, et al., 2003 ; Schoofs, et al., 2010 ). The Japanese translation by Hasegawa was used. Hasegawa (2013 ) reported that Brooding, Reflection, and total RRS scale scores have good internal consistencies (αs =.81,.75, and.93, respectively) and moderate 4-week test-retest reliabilities ( rs =.59,.72, and.75, respectively). These values are identical to those reported for the original scale ( Treynor, et al., 2003 ; see also Hasegawa, Koda, Hattori, Kondo, & Kawaguchi, 2013 ). Confirmatory factor analysis indicated that the model, which assumed that Brooding and Reflection are different factors, fit the data well (CFI = 0.92, RMSEA = 0.08). The fit indices of the two-factor model were better than those of the unidimensional model, in which the 10 items assessing Brooding and Reflection comprised one factor. In addition, the correlations with depression, worry, and self- and external-preoccupation showed that the total RRS and subscales

10 662 A. HASEGAWA, ET AL. have adequate convergent and discriminant validity. Hasegawa (2013) reported that the mean scores for Brooding, Reflection, and the total RRS scale were ( SD = 3.61, range = 5 20), 9.15 ( SD = 3.27, range = 5 20), and ( SD = 13.00, range = 22 78), respectively. In Study 1, the internal consistencies of Brooding, Reflection and total scale of the RRS were.75,.75, and.89, respectively. Brooding was correlated significantly with Reflection ( r =.50, p <.001). Statistical Analysis Student t tests were used to compare group differences. The logistic regression analyses were conducted with each variable as the independent variables, and experience of past depressive episodes as a dependent variable. The present study adopted this method in order to examine the relationships between each variable after controlling for the other variables. R ESULTS Descriptive statistics for all scales are displayed in Table 1. There were no significant group differences for age ( t 180 = 1.09, p =.27, d = 0.18) or sex [χ 2 (1, N = 182) = 0.05, p =.82]. The formerly depressed group scored higher on the IDDL severity than the never-depressed group. The IDDL severity score of the formerly depressed group in this study was slightly lower than that of the formerly depressed patient group reported by Uehara, et al. (1995), and the severity score of the never-depressed group in this study was slightly higher than that of the healthy control group reported by Uehara, et al. (1995). In the present study, the range of the severity score in the formerly depressed group was from 22 to 60 and that in the never-depressed group was from 0 to There was some overlap in IDDL severity scores between participants in the formerly depressed group and the never-depressed group. However, depressive episodes identified by the IDDL were determined by severity and duration responses. In addition, the participants were included in the never-depressed group if they had not experienced depressed mood or loss of interest for over two weeks (i.e., they had experienced only shorter episodes). Therefore, it can be assumed that the two groups were distinctly different. The CES D scores did not differ between the two groups. The mean CES D scores of each group were slightly less than that reported by Hasegawa (2013). These results supported the notion that the formerly depressed group and the never-depressed group differed for depression histories but not for current depression. 9 The range of the IDDL severity score of the currently non-depressed participants in this study (i.e., CES D < 16; n = 235) was from 0 to 60 and the mean score was ( SD = 12.49).

11 DEPRESSIVE RUMINATION AND PAST DEPRESSION 663 TABLE 1 D ESCRIPTIVE STATISTICS FOR EACH SCALE AND GROUP DIFFERENCES IN STUDY 1 Formerly Depressed ( n = 39) Never Depressed ( n = 144) t d Variable M SD M SD IDDL Number of symptoms Severity score CES D RRS Brooding Reflection Total score Note. IDDL = Inventory to Diagnose Depression, Lifetime Version; CES D = Center for Epidemiologic Studies Depression Scale; RRS = Ruminative Responses Scale; d = Cohen's effect size (mean score of formerly depressed group mean score of never depressed group) / pooled SD. p <.01. p <.001. On the RRS, the formerly depressed group scored higher than the never-depressed group on Brooding, Reflection, and total scale. 10 Logistic regression analysis was conducted with CES D, Brooding, and Reflection scores as the independent variables and experience of past depression (yes or no) as the dependent variable ( Table 2 ). Only Brooding was significantly associated with experience of a past depressed episode (OR = 1.18). CES D and Reflection were not associated with past depression. This equation significantly predicted the dependent variable [ χ 2 (3, N = 183) = 19.08, p <.001]. D ISCUSSION As predicted, Brooding was related to past depressive episodes. This result was consistent with previous findings that formerly depressed groups scored higher on Brooding than never-depressed groups ( Joormann, et al., 2006 ; Watkins & Moulds, 2009 ; Joormann & Gotlib, 2010 ; Sanders & Lam, 2010 ). This consistency indicates that Brooding as assessed on the Japanese RRS has similar psychometric properties as other language versions. Also in the present study, the formerly depressed group scored higher on the Reflection subscale than the never-depressed group. However, after controlling for Brooding and the current depression level, Reflection 10 The total RRS score and subscale scores of the currently depressed group that was eliminated by the analyses ( n = 250) were as follows: ( SD = 3.32) for Brooding, ( SD = 3.22) for Reflection, and ( SD = 11.59) for the total scale. The currently depressed group scored higher on the total RRS scale and in the two subscales than the never-depressed group ( t > 6.99, p <.001), and scored higher on Brooding and the total RRS scale than the 392 formerly depressed group ( t 287 > 2.23, p <.03).

12 664 A. HASEGAWA, ET AL. TABLE 2 R ESULT OF LOGISTIC REGRESSION ANALYSIS PREDICTING PAST DEPRESSION IN STUDY 1 Variable B SE Odds Ratio 95% CI Wald p CES D , Brooding , Reflection , was not significantly associated with past depression. These results suggest that the subcomponent of rumination directly associated with past depression was Brooding, not Reflection. Some previous studies showed that formerly depressed groups scored higher on Reflection than the never-depressed group ( Watkins & Moulds, 2009 ; Joormann & Gotlib, 2010 ), but these studies did not control for the correlation between Brooding and Reflection. It is possible that the intercorrelations between the RRS subscales account for these results. The logistic regression analysis indicated that the odds ratio for Reflection was more than 1.00, suggesting that Reflection represents a less maladaptive component of rumination than Brooding but not an adaptive component. Study 2 Study 2 was a replication and extension of Study 1. In line with Study 1, scores on the Brooding and Reflection subscales were compared between the formerly depressed group and the never-depressed group. In addition, worry proneness was assessed and included among the independent variables in the logistic regression analysis. Described above, depressive rumination and worry share some characteristics but have distinct aspects ( Watkins, et al., 2005 ). Some researchers suggested that depressive rumination is a vulnerability factor for depression and worry is a central cognitive process of anxiety disorders (e.g., Nolen-Hoeksema, et al., 2008 ), but previous studies showed mixed results about these suggestions (see Introduction section). If Brooding is related to past depression even after controlling for worry, then Brooding may be a vulnerability factor for depression. M ETHOD Participants Japanese undergraduate students ( N = 414) took part in this study at three universities: Nagoya University, Tokai Gakuin University, and University of the Ryukyus. Although exact demographic information was not recorded, the students at these universities are largely native-speaking Japanese. Participants were recruited in their classes, mainly psychology classes. All participants who agreed to take part in this study completed the questionnaires there. Similar to Study 1, random sampling was

13 DEPRESSIVE RUMINATION AND PAST DEPRESSION 665 not conducted in this study due to practical reasons. All participants received a book card worth 500 yen (approximately 5 dollars) for their participation. The Ethics Committee of Tokai Gakuin University approved the study. The selection criteria for each group were similar to Study 1, with one additional criterion. In the original instructions of the IDDL, participants were instructed to recall their worst lifetime episode of depression. However, some participants may recall their present state and others may recall recent states because those are their worst lifetime episodes. Therefore, the selection criteria were modified to confirm that the participants were currently non-depressed and their answers reflected depressive episodes more than two months in the past. Participants answered two items (persistent depressive mood and loss of interest items) which asked if they had experienced depressive mood or loss of interest for two successive weeks within the past two months. If participants answered yes to either item, their data were eliminated because they had experienced depression recently. The reason for using the past two months is that it is the full remission criteria for being asymptomatic for Major Depressive Disorder. Participants who scored less than 15 points on the CES D and had not experienced depressive mood or loss of interest for two weeks during the past two months were considered currently non-depressed. The formerly depressed group consisted of 27 participants (11 men, 16 women). The mean age of this group was 19.6 yr. ( SD = 1.8; range = 18 to 25). The never-depressed group consisted of 185 participants (95 men, 90 women). The mean age of this group was 18.9 yr. ( SD = 1.1; range = 18 to 23). Measures Inventory to Diagnose Depression, Lifetime Version. This scale was the same as used in Study 1, but a slight modification was made in the instructions. As described above, in Study 1, some participants may recall recent states. In this study the IDDL was used to identify the experiences of past depression, by adding the instruction that the recalled experience must be before the previous two months. In Study 2, the internal consistency reliability of severity was.90 in the final sample analyzed in Study 2 ( N = 212). Center for Epidemiologic Studies Depression Scale and Ruminative Responses Scale. These measures were same as used in Study 1. The internal consistency reliability of the CES D in the sample was low (.46; N = 212), similar to Study 1. However, using the data of the full sample in this study ( N = 414), the internal consistency of the CES D was.76. The internal consistencies of Brooding, Reflection, and the RRS total scale in the final sample analyzed in Study 2 were.75,.72, and.88, respectively. Brooding was correlated significantly with Reflection ( r =.39, p <.001).

14 666 A. HASEGAWA, ET AL. Penn State Worry Questionnaire (PSWQ; Meyer, et al., 1990 ). The PSWQ is a self-report scale designed to measure the frequency and intensity of worry. This scale includes 20 items, each rated on a five-point rating scale with anchors 1: Not at all typical of me and 5: Very typical of me. Meyer, et al. (1990 ) showed that the PSWQ has high internal consistency ( α =.91.95), high test-retest reliability ( r =.74.93) over 2- to 10- week intervals, and good convergent and discriminant validity in terms of the correlation with constructs such as state and trait anxiety, cognitive and somatic anxiety, depression, and social desirability. Sugiura and Tanno (2000 ) translated the PSWQ into Japanese, and confirmed adequate reliability and validity of the scale. Based on a study with 315 undergraduate students, they reported that the mean score of the Japanese PSWQ was ( SD = 11.90). In the present study, the internal consistency of the PSWQ was.90. Persistent depressive mood and loss of interest items. Two items were developed for the present study on the basis of criteria A of the DSM IV major depressive episode. These items asked if participants had experienced depressive mood or loss of interest for two weeks within the past two months. The two questions were as follows: Within the past two months, has there been a time when you were depressed, or were down for most of the day, nearly every day for as long as two weeks? and Within the past two months, has there been a time when you were a lot less interested in most things, or were unable to enjoy things you used to enjoy for as long as two weeks? Participants responded yes or no to each question. Similar questions have been utilized by many previous studies (e.g., Ma and Teasdale, 2004 ). However, psychometric properties of these two items had not been examined. R ESULTS Descriptive statistics for all scales are displayed in Table 3. There were significant group differences of age ( t 210 = 2.14, p <.05, d = 0.64) but not sex [χ 2 (1, N = 212) = 1.06, p =.30]. All analyses described below were repeated (i.e., t tests and logistic regression analyses), controlling for age, and observed similar results (e.g., p values and odds ratios). Therefore, the analyses described below were not controlled for age. The formerly depressed group scored higher on the IDDL severity than the never-depressed group. The IDDL severity score of the formerly depressed group in this study was slightly lower than that of the formerly depressed patients group reported by Uehara, et al. (1995 ), and the severity score of the never-depressed group in this study was slightly higher than that of the healthy control group reported by Uehara, et al. (1995 ). In the present study, the range of the severity scores in the formerly depressed group

15 DEPRESSIVE RUMINATION AND PAST DEPRESSION 667 TABLE 3 D ESCRIPTIVE STATISTICS FOR EACH SCALE AND GROUP DIFFERENCES IN STUDY 2 Formerly Depressed ( n = 27) Never Depressed ( n = 185) t d Variable M SD M SD IDDL Number of symptoms Severity score CES D RRS Brooding Reflection Total score PSWQ Note. IDDL = Inventory to Diagnose Depression, Lifetime Version; CES D = Center for Epidemiologic Studies Depression Scale; RRS = Ruminative Responses Scale; PSWQ = Penn State Worry Questionnaire; d = Cohen's effect size: (mean score of formerly depressed group mean score of never depressed group) / pooled SD. p <.01. p <.001. was 24 to 68 and that in the never-depressed group was 0 to Similar to Study 1, there was some overlap in IDDL severity scores between the two groups. However, for the same reasons described in Study 1, it was assumed that the two groups were distinctly different. The CES D scores did not differ between the two groups. These results indicate that the formerly depressed group and the never-depressed group differed for histories of depression but not for current levels of depression. On the RRS, the formerly depressed group scored higher than the never-depressed group on Brooding, Reflection, and the total RRS scale. There were no group differences for the PSWQ scores. 12 In line with the analysis in Study 1, logistic regression analysis was conducted with CES D, Brooding, and Reflection scores as the independent variables and experience of past depression (yes or no) as the dependent variable. Table 4 shows the 11 The range of the IDDL severity score of the currently non-depressed participants in this study (i.e., CES D < 16 and had not experienced persistent depressive mood and loss of interest for two weeks within the past two months; n = 249) was 0 to 68, and the mean score was ( SD = 12.03). 12 The total RRS scale and subscale scores and PSWQ score of the currently depressed group that scored more than 16 points on the CES D and were eliminated by the analyses ( n = 145) were as follows: ( SD = 3.11) for Brooding, ( SD = 3.19) for Reflection, ( SD = 10.64) for the total RRS scale, and ( SD = 9.75) for the PSWQ. The currently depressed group scored higher on all scales than the never-depressed group ( t328 > 7.28, p <.001), and scored higher on Brooding and PSWQ than the formerly depressed group ( t 170 > 2.32, p <.03).

16 668 A. HASEGAWA, ET AL. results of the analysis. Consistent with Study 1, Brooding was significantly associated with experience of past depressive episodes (OR = 1.14). In contrast to the findings of Study 1, the odds ratio for Reflection was stronger than that for Brooding (OR = 1.27). CES D was not associated with past depression (OR = 0.93). This equation significantly predicted the dependent variable [ χ 2 (3, N = 212) = 25.58, p <.001]. Next, logistic regression analysis was conducted with CES D, Brooding, Reflection, and PSWQ scores as the independent variables and experience of past depression as the dependent variable. Consistent with the above result, Brooding and Reflection were significantly associated with experience of past depressive episodes, but CES D was not (see Table 4 for the detailed results). In addition, PSWQ was not associated with past depression (OR = 0.99). This equation significantly predicted the dependent variable [ χ 2 (4, N = 212) = 25.82, p <.001). TABLE 4 R ESULTS OF LOGISTIC REGRESSION ANALYSES PREDICTING PAST DEPRESSION IN STUDY 2. B SE Odds Ratio 95% CI Wald p CES D Brooding Reflection B SE Odds Ratio 95% CI Wald p CES D Brooding Reflection PSWQ Note. Top half of table: Model 1 with CES-D, Brooding, and Reflection as predictors; bottom half is Model 2 adding PSWQ. D ISCUSSION Student t tests and logistic regression analysis showed that current Brooding scores were related to a past history of depression. These results were consistent with the results of Study 1 and previous studies which showed that Brooding was related to past major depressive episodes ( Joormann, et al., 2006 ; Watkins & Moulds, 2009 ; Joormann & Gotlib, 2010 ; Sanders & Lam, 2010 ), indicating that Brooding as assessed on the Japanese RRS has similar relationships with previous depression as found for other language versions. Study 2 importantly shows that Brooding is related to a past history of depression after controlling for worry. The score on the PSWQ did not differ between the formerly depressed group and the nev-

17 DEPRESSIVE RUMINATION AND PAST DEPRESSION 669 er-depressed group. These findings indicate that the brooding component of rumination is a vulnerability factor for depressive episodes rather than worry, which is a construct similar to depressive rumination. Watkins and Moulds (2007, 2009 ) showed that the formerly depressed group scored higher on the PSWQ than the never-depressed group. Their findings are inconsistent with the results of the current study. However, the formerly depressed group in Watkins and Moulds (2007, 2009 ) scored higher on the measure of depression. It is possible that small group differences in the severity of depression might explain the differences in worry (in the present study, there were no significant group differences on the CES D score). Also, the differences in findings regarding the PSWQ score may be due to the screening method that was used to select participants in each group (the Structured Clinical Interview for DSM IV or the IDDL). In contrast to the findings of Study 1, in the logistic regression analysis Reflection was significantly associated with the experience of past depression. Moreover, the odds ratio for Reflection was stronger than that for Brooding. The explanation of this inconsistency is important because many research articles have assumed that Reflection is an adaptive component (e.g., Treynor, et al., 2003 ). There were slight differences between the samples of Studies 1 and 2 in terms of age, sex ratio, and the group selection criteria. Slight differences in the samples or the moderate reliability of the RRS subscales might explain the different relationships between Reflection and previous depression. In addition, it is possible that moderator variables may be one factor that contributes to this inconsistency. The interactions between Reflection and other cognitive and behavioral variables, such as negative information stored in long-term memory and avoidant behavioral patterns, as well as environmental factors, might lead to adverse outcomes. However, the results must be interpreted cautiously because in the present study Reflection is related to only to past depression. It is possible that some people use reflection as a result of experiences of depressive episodes. To the authors knowledge, no study has compared Brooding with Reflection in terms of their predictive powers for future onset and relapse of major depressive episode. Future research should re-examine whether formerly depressed groups score higher on Reflection than never-depressive groups. If it were to be established that depressed individuals have higher Reflection scores, it would be important to identify whether their reflections are maladaptive or benign. The findings were consistent with the proposal that Brooding is a maladaptive component of rumination ( Treynor, et al., 2003 ). This implies that cognitive behavioral therapy which targets the brooding components of rumination may lead to prevention of depression in Japanese populations as well as Western populations. There are three empirically sup-

18 670 A. HASEGAWA, ET AL. ported therapies that target maladaptive components of rumination in cognitive behavioral therapies: mindfulness-based cognitive therapy ( Segal, Williams, & Teasdale, 2002 ), metacognitive therapy ( Wells, 2009 ), and rumination-focused cognitive behaviour therapy (RFCBT; Watkins, Scott, Wingrove, Rimes, Bathurst, Steiner, et al., 2007 ). For example, in RFCBT rumination is conceptualized as consisting of abstract, evaluative cognitive processing and avoidance behaviors; the goal of RFCBT is to replace these with concrete, process-focused, and specific cognitive processing, as well as with more helpful approach behaviors. Watkins, Mullan, Wingrove, Rimes, Steiner, Bathurst, et al. (2011) showed that RFCBT reduces residual depressive symptoms and prevents relapses of major depressive episodes in individuals meeting criteria for medication-refractory residual depression. It is plausible that RFCBT, or other empirically supported therapies, can prevent depressive episodes in Japanese university students with prolonged brooding rumination who are vulnerable to depression. Limitations and Conclusions There are certain limitations to the present study. First, because participants were not randomly selected, it is possible that the current sample was not a representative sample of the undergraduate population. Second, the present study identified the status of past depression using self-report questionnaires, rather than using structured clinical interviews. As described above, the reason for non-significant group differences in the PSWQ score between the formerly depressed group and the never-depressed group may have been due to the screening method (i.e., selection with the IDDL). In addition, items that were specially developed for the present studies were used to assess the persistent depressive mood and loss of interest. However, it is not clear whether participants' responses to these items were the same as that for structured clinical interviews. It is suggested that future studies should re-examine the relationships among Brooding, Reflection, and past depression by using structured clinical interviews. Finally, participants were university students and not a clinical sample. Future studies should re-examine the current findings by using clinical samples. In these studies, Brooding was consistently related to past depression. This result is consistent with previous findings obtained with other language versions ( Joormann, et al., 2006 ; Watkins & Moulds, 2009 ; Joormann & Gotlib, 2010 ; Sanders & Lam, 2010 ). The consistency between other language versions, as well as with previous findings by Hasegawa (2013), suggest that psychometric properties of Brooding as assessed by the Japanese RRS are similar to that of other countries and have universal validity. In addition, Study 2 demonstrated that the brooding component of rumination is a vulnerability factor for depressive episodes rather than for worry, which is a construct similar to depressive rumination. This find-