باورهای مثبت درباره نشخوار فکری در افسردگی - همانندسازی و گسترش

Papageorgiou and Wells (2001) reported that positive beliefs about rumination were elevated in depressed patients, using the Positive Beliefs about Rumination Scale (PBRS). However, this study had a relatively small sample and there is a possibility that there were confounds within this measure between the severity of depressed mood and endorsement of beliefs. This study attempted to replicate these findings within a larger sample, and to extend these findings to recovered depressed patients, who are known to demonstrate elevated rumination. Furthermore, a version of the PBRS adapted to reduce confounds with mood state and valence was also used. Consistent with predictions, both currently depressed and recovered depressed patients had elevated scores on both the original and adapted PBRS compared to never-depressed controls. The present findings confirm that positive beliefs about rumination are genuinely associated with elevated levels of rumination in depression-prone groups and indicated that previous similar positive findings (Papageorgiou & Wells, 2001) were not the result of methodological confounds such as criteria contamination in the PBRS or small sample size.

Depressive rumination (Nolen-Hoeksema, 1991) has been defined as thoughts and behaviours that repetitively focus an individual’s attention on his or her negative feelings, and the nature and implications of these feelings. Theoretical models (e.g. Teasdale & Barnard, 1993) and empirical findings have suggested that rumination may be a core cognitive process in depression. Thus, depressed patients and recovered depressed patients report more rumination than never-depressed controls (Nolen-Hoeksema, 2000 and Roberts et al., 1988), with rumination predicting the maintenance of depressive symptoms in clinically depressed groups (Kuehner and Weber, 1999 and Nolen-Hoeksema, 2000) and the onset of depression in non-depressed groups (e.g. Just and Alloy, 1997, Nolen-Hoeksema et al., 1994 and Spasojevic and Alloy, 2001). Furthermore, in experimental studies, compared to distraction, rumination exacerbates depressed mood and negative cognition in volunteers in either a naturally occurring or induced dysphoric mood (e.g. Lyubomirsky and Tkach, 2004 and Nolen-Hoeksema and Morrow, 1993). Given the empirical findings suggesting that rumination is depressogenic, why do some people show a persistent tendency to ruminate (Nolen-Hoeksema, 1991)? One potential explanation is that people who ruminate hold beliefs about rumination that encourage their tendency to ruminate. Beliefs about thinking processes, such as how thinking works, how controllable and how normal it is, and about the functions and the consequences of particular types of thinking are known as metacognitive beliefs. Recently, metacognitive beliefs have been hypothesised to be involved in the development of negative recurrent thinking such as worry and rumination. Indeed, theoretical models such as the Self-Regulatory Executive Function model (Wells & Matthews, 1994) have hypothesised that metacognitive beliefs are involved in the development and persistence of emotional disorders in general. The evidence to date is consistent with these hypotheses. Thus, patients with Generalised Anxiety Disorder (GAD) have positive metacognitive beliefs about worry, which emphasise the advantages of worry, e.g. worry is helpful for problem solving (Borkovec and Roemer, 1995 and Freeston et al., 1994), and negative metacognitive beliefs, which emphasise the risks and negative consequences of worry, e.g. that worry is uncontrollable (Davis and Valentiner, 2000 and Wells and Carter, 1999). The positive metacognitive beliefs are hypothesized to increase the selection of worry as a strategy in response to a difficulty, and then the negative metacognitive beliefs are hypothesized to lead to further “worry about worry” itself (Wells, 1995). Given the similarities observed between worry and rumination (Borkovec et al., 1998, Fresco et al., 2002, Segerstrom et al., 2000 and Watkins et al., in press), it is perhaps not surprising that positive and negative metacognitive beliefs about rumination are also found in dysphoric and depressed people. Lyubomirsky and Nolen-Hoeksema (1993) reported that dysphoric students who ruminated about their mood felt that they were gaining insight into their problems and their emotions. Watkins and Baracaia (2001) found that 80% of dysphoric ruminators reported at least one perceived benefit of rumination, such as increasing self-awareness, understanding depression and/or solving problems, and 98% reported at least one disadvantage of rumination. Using a semi-structured interview, Papageorgiou and Wells (1999) found that depressed patients believed that rumination was helpful for solving problems and understanding depression, but also that rumination was uncontrollable and dangerous. Papageorgiou and Wells (2001) developed and validated the Positive Beliefs about Rumination Scale (PBRS), which assessed the extent to which people felt rumination was helpful. The PBRS positively correlated with extent of rumination, and patients with major depression had elevated scores on the PBRS compared to patients with panic disorder, patients with social phobia and non-clinical controls. However, Papageorgiou and Wells (2001) used a small sample (n = 12 in each group), such that replication in a larger sample is essential before we can consider elevated positive metacognitive beliefs about rumination to be a reliable finding in depression. Thus, the first aim of this study is to test that a larger sample of patients with major depression will have higher PBRS scores than never-depressed controls. A second potential limitation of the Papageorgiou and Wells (2001) study is that the elevated scores on the PBRS for depressed patients may be due to confounds within this measure between the severity of depressed mood and endorsement of beliefs about depressive rumination (i.e. criterion contamination). All of the items on the PBRS refer to rumination and five out of nine items refer to “my depression” (see Table 1). Furthermore, rumination was defined to participants as prolonged and repetitive depressing thinking. Thus, it is possible that the severity of depression contaminates the measurement of beliefs about how helpful it is to ruminate about depression. For a depressed patient, the PBRS items may be more relevant and meaningful than for a never-depressed control simply because of their increased reference to depression, and thus, endorsed more for that reason. Likewise, depressed participants may endorse the items on the PBRS more than never-depressed participants because the items on the PBRS reflect a more negative valence, and, are thus, more consistent with the mood state and response bias of the depressed patients. Obviously, there is a trade off between criterion contamination and construct validity when considering responses to depression: Nonetheless, we sought to investigate whether the effects on the PBRS could be replicated when criterion contamination is reduced.