An experimental investigation of the cognitive vulnerability to depression

Abstract

The present study employed an experimental design, to examine the role of metacognitive processing in the prevention of relapse to depression. Eighty remitted depressed participants were randomly allocated to receive training in the metacognitive style of rumination, distraction, acceptance or no training control prior to a negative mood induction. Rumination prolonged the intensity of the negative mood consistent with no training, whereas both distraction and acceptance reduced the intensity of the negative mood. Changes in attitudes were only found in the acceptance condition, as participants in this condition reduced negative attitudes towards negative experiences. These results are consistent with information processing theory, and imply that acceptance-based preventative interventions may operate by both reducing the intensity of sad moods and altering one's attitudes towards temporary moments of sadness.

Introduction

Given the evidence that depression is often a recurrent disorder (e.g., Judd, 1997), recent efforts have been directed to the prediction of relapse and relapse prevention (Dobson & Ottenbreit, 2004; Teasdale et al., 2002). Teasdale, Segal, and Williams (1995) have described an information processing theory for relapse that proposes that formerly depressed individuals are at risk for relapse because of an information processing style that perpetuates the accessibility of negative schema, memories and attitudes during periods of low mood. When these schemas are continuously activated, negative specific meanings are generated such as negative predictions for the future, attributions of failures to personal inadequacy, negative evaluations of interpersonal interactions, and retrieval of memories of previous failures or difficulties. Teasdale et al. (1995) postulated that when experiencing negative affect, individuals at risk for depressive relapse tend to reactivate the thinking styles associated with previous sad moods. Specifically, they tend to ruminate or dwell on the reasons for their low mood, which in turn perpetuates a negative cognitive set and through this chronicity, predisposes individuals to future depressive relapse.

Rumination has been defined in the literature as behaviors and thoughts that focus one's attention on depressive symptoms, and the implications and consequences of these symptoms (Nolen-Hoeksema, 1991). Individuals who ruminate tend to negatively appraise themselves, their feelings, behaviors, situations, life stresses, and ability to cope. By engaging in rumination, negative self-schemas become continuously activated, leading to the continuation of distorted beliefs and perceptions of past experiences. In support of this model, Nolen-Hoeksema and Morrow (1991) found that individuals reporting a ruminative style prior to an earthquake also reported more symptoms of depression following the earthquake. In other research, dysphoric individuals who were instructed to ruminate following a mood induction demonstrated more negative, biased interpretations of events and impaired problem solving in the presence of negative mood when compared to dysphoric individuals who distract (Lyubomirsky & Nolen-Hoeksema, 1995). Rumination has also been found to predict the severity of depressive symptoms (Nolen-Hoeksema, 2000) and to enhance negativity in the recall of autobiographical memories (Lyubomirsky, Caldwell, & Nolen-Hoeksema, 1998).

It has been proposed that a ruminative information processing style is the result of problems with metacognition, or thinking about thinking (Nelson, Stuart, Howard, & Crowley, 1999). Metacognition serves two functions including the monitoring of thoughts and emotions, and the capacity to exert control over thoughts and feelings. In particular, it has been proposed that rumination is the result of a ‘positive’ metacognitive appraisal of negative thinking (Papageorgiou & Wells, 2001); that is, individuals who ruminate may do so in the belief that repeated thinking about problems will somehow lead to their solution.

Individuals can also make a ‘negative’ metacognitive appraisal of their thoughts (i.e. “I should avoid these negative thoughts”), which might lead to attempts to avoid or distract from the negative thoughts and feelings. Distraction is defined as the purposeful act of shifting attention away from the symptoms of depression towards more pleasant or neutral thoughts and actions (Nolen-Hoeksema & Morrow, 1991). Research suggests that depressed individuals who engage in distraction demonstrate significantly decreased depressed mood when compared to individuals who ruminate (Nolen-Hoeksema & Morrow, 1991). Unfortunately, although distraction may be sufficient to temporarily dispel a negative mood state through the deployment of attention, the schemas underlying negative states are still readily accessible in memory and are likely to recapture attention when the distraction task is completed. In the absence of distraction, individuals will still process information according to these negative schemas when faced with an experience that is highly personally relevant, leading to the re-emergence of a depressive response style and stronger vulnerability to depression (Teasdale et al., 1995).

A third alternative to a positive or a negative metacognitive appraisal is to be aware of negative thoughts and feelings, but to remain open toward these experiences. Individuals can become aware of the present moment including negative experience, and evaluate the thoughts and feelings as simply passing events in the mind. There is a heightened sense of being in the ‘here and now’, which is thought to assist in the disengagement from ruminative processing (Teasdale et al., 1995). Evidence suggests that when compared to never depressed people, depressed individuals showed significantly less evidence of metacognitive awareness in relation to thoughts and feelings in their accessed autobiographical memories of negative experiences (Teasdale et al., 2002). In addition, a deficit in metacognitive awareness significantly predicted relapse in recovered depressed individuals over a 5-month follow-up (Teasdale et al., 2000), suggesting the prevention of relapse might occur through changes in metacognitive awareness and acceptance.

The implication of information processing theories of relapse is that preventative interventions can exert influence by changing the metacognitive appraisal made in times of negative experience, thereby altering the patterns of cognitive processing activated during negative mood states. It has been proposed that this metacognitive stance of awareness and acceptance can alter individuals’ relationship to their thoughts and feelings by creating greater decentering from them and their personal meaning, thereby reducing the magnitude of negative moods and dysfunctional attitudes (Segal, Williams, & Teasdale, 2002). Several theorists have discussed the concept of acceptance as an important therapeutic tool in the treatment of emotional disorders (cf. Hayes, 2004; Linehan, 1989). Specifically related to depression, Mindfulness-Based Cognitive Therapy (MBCT; Segal et al., 2002) builds upon the theoretical framework of the information processing theories, and teaches individuals who have recovered from depression to disengage from ruminative processing, by increasing their awareness and acceptance of negative thoughts and feelings, at times of potential relapse (Teasdale et al., 2000). Recent studies have shown that MBCT is efficacious in reducing the risk of relapse in individuals who have suffered from previous episodes of depression. Two randomized trials that compared MBCT to treatment as usual demonstrated that MBCT reduced the risk for relapse by 26–42% (Ma & Teasdale, 2004; Teasdale et al., 2000).

While results from the efficacy research on MBCT are promising, there have been few experimental studies that have investigated the proposed mechanism behind MBCT. Watkins, Teasdale, and Williams (2003) conducted a study in which never depressed participants underwent a negative mood induction. They were then randomly assigned to either an ‘awareness’ group, which received questions designed to increase metacognitive awareness or a control group, which received distraction questions. As predicted by the information processing theory of depression, in comparison to the control group, a significantly greater proportion of participants in the awareness group demonstrated recovery from the induced negative mood and reported shifts in perspective concerning mood states.

An important step in the investigation of MBCT is the study of the effects of training in metacognitive awareness and acceptance (referred to as ‘acceptance’ in the present study) in reducing negative mood states in formerly depressed individuals, who are theoretically at risk for relapse. Although, there are a number of studies that have investigated the role of rumination in depression in college samples and currently depressed individuals (Nolen-Hoeksema, 2000; Nolen-Hoeksema and Morrow, 1991), there are far fewer studies that have studied experimentally the effect of a rumination induction in individuals who have remitted from depression.

The current study was designed to test the cognitive vulnerability to depression in a well-controlled experimental design with procedures in place to enhance internal validity. Adapted from Watkins et al. (2003), formerly depressed participants received training in rumination, distraction, acceptance or no training control prior to a negative mood induction. Following the negative mood induction, participants engaged in the training they had received previously, and the intensity of the negative mood state and the time to recovery from the negative mood was measured. The effect of the conditions on the intensity of induced moods and changes in attitudes towards negative experience were examined. It was predicted that:

• Rumination would significantly increase the intensity of negative mood, while distraction and acceptance would decrease the intensity of negative mood.

• Participants who ruminated would be less likely to recover from the negative mood state compared to those individuals who accepted or distracted.

• After training in acceptance, participants would demonstrate an increased acceptance towards depressive experience, reduced negative and positive attitudes towards negative experiences, and reduced positive beliefs about rumination.