Repetitive negative thinking as a predictor of depression and anxiety: A longitudinal cohort study

Highlights

• Repetitive negative thinking (RNT) underlies rumination and worry.

• RNT is a risk factor for severity, persistence and relapse of depression and anxiety.

• RNT as a pathological trait deserves more attention in clinical diagnosis and treatment.

Abstract

Background

Repetitive Negative Thinking (RNT) is assumed to be a transdiagnostic proximal risk factor in depression and anxiety. We examined the prospective relations of disorder-dependent as well as disorder-independent measures of RNT with depression and anxiety outcomes.

Methods

In a prospective cohort study, 1972 adults completed a 3-year follow-up period (attrition = 12.6%). DSM-IV diagnoses were assessed with the CIDI, symptom severity with the IDS and BAI, and RNT with measures for perseverative thinking (PTQ), rumination (LEIDS-R) and worry (PWQ).

Results

The common dimension of our RNT measurements (according to Confirmatory Factor Analysis) was significantly associated with comorbidity among depressive and among anxiety disorders, severity of depressive and anxiety symptoms, as well as persistence and relapse of depressive and anxiety disorders. Additionally, a specific factor for rumination predicted comorbidity of depressive disorders, comorbidity of anxiety disorders and relapse of depressive disorder, while a specific factor for worry predicted comorbidity of anxiety disorders and relapse of anxiety disorders, although to a lesser extent than general RNT.

Limitations

The present study relied solely on self-report measures of RNT and controlling for baseline demographic and clinical variables greatly attenuated the predictive value of RNT.

Discussion

Disorder-independent RNT may be a similar underlying process present across depressive and anxiety disorders. It seems more important than the representation of this process in disorder-specific cognitive content such as rumination in depression and worry in anxiety. RNT as a pathological trait deserves more attention in clinical diagnosis and the transdiagnostic treatment of comorbid depression and anxiety in particular.

Introduction

Repetitive, prolonged, and recurrent thought (such as worry, rumination, reflection, and problem solving) is part of the human condition and can have both unconstructive and constructive consequences (see Watkins (2008) for an extensive overview). Unconstructive repetitive negative thinking as related to emotional problems has been defined as a style of thinking about one's problems or negative experiences that is repetitive, intrusive, and difficult to disengage from (Ehring and Watkins, 2008, Watkins, 2008). Although RNT may be heightened during episodes of psychiatric disorder, RNT is considered to constitute a stable trait-like feature. As such RNT has been conceptualized as a transdiagnostic risk factor implicated in the onset and maintenance of various depressive and anxiety disorders (Harvey et al., 2004, McEvoy et al., 2013). Current measures of RNT are mostly focused on a specific content (such as ruminating about depression or worrying about future threats) and are therefore disorder-specific. For example, depressive rumination has been characterized as “repetitively focusing on the fact that one is depressed; on one's symptoms of depression; and on the causes, meanings, and consequences of depressive symptoms” (Nolen-Hoeksema, 1991, p. 569). In most studies depressive rumination is measured with the Ruminative Responses Scale developed to assess rumination that is related to depression (Treynor et al., 2003). Worry has been characterized as “a chain of thoughts and images, negatively affect-laden, and relatively uncontrollable” (Borkovec et al., 1983, p.10). The Penn State Worry Questionnaire (PSWQ) is the most frequently used scale to capture the generality, excessiveness, and uncontrollability dimensions of pathological worry (Meyer et al., 1990).

Consistent with a transdiagnostic perspective, rumination and worry are present across a number of different psychiatric disorders, although rumination may be relatively more pronounced in depression and worry in generalized anxiety disorder (GAD) (Olatunji et al., 2010, Olatunji et al., 2013). There are more similarities than differences across the processes of worry and rumination, including the fact that they are repetitive, difficult to control, negative in content, predominantly verbal, and relatively abstract (Watkins, 2008). The only replicated diagnosis-specific differences concern the thought content and temporal orientation, with depressive rumination more likely to be past-oriented and worry more likely to be future-oriented (Ehring and Watkins, 2008).

The study of RNT is complicated by the fact that practically all measures relate either to rumination or worry, the assessment of which include content-specific or disorder-specific items (McEvoy et al., 2013). To examine the relations between disorder-independent RNT and psychopathology, two generic RNT measures have been developed and validated: the Repetitive Thinking Questionnaire (RTQ; Mahoney et al., 2012, McEvoy et al., 2010, McEvoy et al., 2014) and the Perseverative Thinking Questionnaire (PTQ; Ehring et al., 2012, Ehring et al., 2011). This latter measure is used in the present study and comprises items based on core characteristics of RNT (such as repetitiveness, intrusiveness and difficulty to disengage from) to capture RNT as a trait.

Cross-sectional studies with the RTQ and PTQ in non-clinical (Ehring et al., 2012, Ehring et al., 2011, McEvoy et al., 2010) and clinical (Ehring et al., 2011, Mahoney et al., 2012) samples showed that these disorder-independent measures of RNT are strongly associated with severity of depression, anxiety and general distress. In addition, it has been found that PTQ scores prospectively predict severity of depressive symptoms in a non-clinical sample (Topper et al., 2014), also after controlling for baseline severity (Raes, 2012). Given the high overlap among different measures for RNT, a few studies have tried to identify common variance across measures of RNT using structural equation modelling (Arditte et al., 2016, Hur et al., 2017, McEvoy and Brans, 2012, Segerstrom et al., 2000, Spinhoven et al., 2015). Overall, these studies show that the shared variance of perseverative thinking, worry and rumination scales is very large and that an underlying factor for RNT is associated with severity of depressive and anxiety symptoms (Arditte et al., 2016, Hur et al., 2017, McEvoy and Brans, 2012, Segerstrom et al., 2000, Spinhoven et al., 2015) as well as with individual depressive and anxiety disorders and comorbidity among depressive and among anxiety disorders (Spinhoven et al., 2015). However, over and above a general factor accounting for the commonality shared by the RNT measures, rumination and worry measures still show a differential and unique although smaller effect on measures for symptom severity. In these studies the unique variance in rumination or brooding proved to be related with depression (McEvoy and Brans, 2012, Segerstrom et al., 2000, Spinhoven et al., 2015) and the unique variance in worry with anxiety outcomes (Hur et al., 2017, Spinhoven et al., 2015) (but see Topper et al., 2014 for an exception). Besides some prospective studies of RNT for the course of anxiety and depression symptoms in non-clinical student samples (Raes, 2012, Topper et al., 2014), there are no clinical studies examining the degree to which RNT or shared versus unique aspects of RNT are prospectively associated with depression and anxiety outcomes.

To fil this gap, we examined to what extent common versus unique aspects of RNT are predictive of comorbidity among depressive and anxiety disorders, severity of depressive and anxiety disorders, as well as persistence and relapse of depressive and anxiety disorders. We hypothesized that a general factor of RNT would be associated with each of these outcomes and that in addition specific factors for rumination and worry would be differentially related to depression and anxiety outcomes, respectively.