Introduction

Rumination is the term for a pattern of repetitive, self-focused thoughts in response to an emotional state. Rumination has a big effect on someone's well-being. The more someone engages in rumination, the more likely it is that he or she will experience sadness, anger and have a poor sleep quality. Rumination is also linked to psychopathology. For example, people who ruminate often are more likely to develop major depression later in life, experience more anxiety symptoms and have more problems with alcohol abuse. 

Rumination is correlated to different forms of psychopathology. However, most studies have focused on depressive rumination. There is less known about other forms of rumination, such as anger rumination. There have been a few studies conducted and those show that as well anger as depression rumination are related to psychopathology. Ciesla, Dickson, Anderson and Neal found that anger rumination is linked to higher alcohol consumption in a week, but depressive rumination is not. Another study conducted by Baer and Sauer found that borderline personality disorder is linked more to anger rumination than to depressive rumination. 

Two other studies found that only anger rumination was associated with anger, overt aggression and relational aggression. Depressive rumination was linked to depressive symptoms and had a negative association with overt aggression. So, these studies suggest that different kinds of rumination (depressive or anger) may be differentially linked with psychopathology. However, the studies that have been conducted have only focused on individual outcomes or discrete disorders (depression) instead on looking at the transdiagnostic relations between the different subtypes of rumination. A transdiagnostic approach means that common features are examined (so, shared genes or temperament) which divide general psychopathology from normality and contribute to internalizing psychopathology (major depressive disorder, generalized anxiety disorder) and externalizing psychopathology (antiosocial personality disorder, substance use disorder). 

Because the correlations within internalizing and externalizing psychopathology are higher than the correlations between them, this shows that there is indeed a distinction between these kinds of psychopathology. By examining broad-band specific features (features that differentiate between internalizing and externalizing psychopathology), this can help to understand why some individuals are at a higher risk for internalizing disorders than externalizing disorders and vice versa.

The current study

In this study, it is predicted that anger and depressive rumination are best described by two correlated factors, instead of being just one factor (so, it are two separate things). The researchers then looked at whether focusing on the process versus on the content has implications for understanding internalizing and externalizing psychopathology. 

Based on previous transdiagnostic research on depressive rumination, the authors of the article hypothesized that depressive and anger rumination would be associated with both internalizing and externalizing psychopathology.  They also thought that the degree to which an individual ruminates, was associated with more psychopathology. In addition, they expected that the emotional focus of the rumination (sadness versus anger) would be differentially associated with psychopathology. They also expected that depressive rumination would lead to internalizing psychopathology and that anger rumination would lead to externalizing psychopathology such as aggression and hostility. 

During their analyses, they allowed for gender differences in the relationship between depressive rumination, anger rumination and psychopathology. This was done because in previous research, higher levels of depressive rumination had been found in woman compared to in men. However, the literature suggests that there would be no gender differences in anger rumination. There have also been gender differences reported in psychopathology: internalizing disorders are more prevalent in women and externalizing disorders are more prevalent in men. Other studies have shown that gender moderates the relation between rumination and alcohol problems: rumination predicts alcohol problems later in life, only in women! Based on these findings, the authors of this article have decided to include gender as a potential moderator.

Method

Participants

The participants in this study were 764 young adults, from 382 same-sex twin pairs. These twin pairs participated in the Colorado Longitudinal Twin Study (LTS).

Measures

Depressive rumination

The participants in the study completed two measures of depressive rumination: the Rumination-Reflection Questionnaire (RRQ) and the 10-item revised version of the Ruminative Response Scale (RRS). The RRS is a 24-item scale which measures rumination (RRQ-Ru) and reflection (RRQ-Re) on a scale from 1 (strongly disagree) to 5 (strongly agree). The RRQ-Ru measures negative self-focused thoughts and the RRQ-Re measures self-reflection.

Anger rumination

The Anger Rumination Scale (ARS) is a 19-item scale which is designed to measure the cognitions (thoughts) that emerge during and after an anger episode. The items in the ARS are rated on a scale from 1 (almost never) to 4 (almost always). These items are also divided into four subscales: angry afterthoughts ("I re-enact the anger episode in my mind after it has happened), thoughts of revenge ("I have long living fantasies of revenge after the conflict is over"), angry memories ("I think about certain events from a long time ago) and understanding causes ("I think about the reasons people treat me badly"). 

Psychopathology

Participants completed the major depressive disorder (MDD), generalized anxiety disorder (GAD) and antisocial personality disorder (ASPD) from the Diagnostic Interview Schedule-IV. This interview was designed to diagnose the major psychiatric disorders which are in the DSM-IV.

Relations of rumination with psychopathology

Are depressive and anger rumination both associated with internalizing and externalizing psychopathology?

Yes. All the correlations between rumination and psychopathology were significant, which means that both forms of rumination are associated with more psychopathology.

Are depressive and anger rumination differentially associated with internalizing and externalizing psychopathology?

Yes. The correlation between depressive rumination was higher with internalizing psychopathology than with externalizing psychopathology.  Aggressive rumination is associated equally with both forms of psychopathology.

Are internalizing or externalizing psychopathology equally associated with anger and depressive rumination?

Yes. Anger rumination and depressive rumination were associated equally with externalizing psychopathology in both men and women.

Discussion

So, the results of this study suggest that both anger and depressive rumination are associated with internalizing and externalizing psychopathology. Depressive rumination is more strongly associated with internalizing psychopathology compared to anger rumination. 

Anger and depressive rumination are two common characteristics of psychopathology, but it is still important to look at their independent associations with internalizing and externalizing psychopathology. The results of this study also support a two-factor model of anger and depressive rumination. Addressing both the process and emotional content of rumination is important in clinical practice and research. And, because ruminative thought processes are a common feature of psychopathology, this should be a key target in clinical treatments.