- New research that uses various methodologies has identified a causal link between relationship distress and depression.
- The association between the two persists across genders, cultures, and types of romantic relationships.
- Couples therapy tends to reduce both relationship distress and symptoms of depression.
In the May 2021 issue of Annual Review of Clinical Psychology, lead author Mark Whisman and colleagues explore evidence for a causal link between romantic relationship distress and depression. The authors contend that “the existing body of research evidence supports the claim that relationship distress is a causal risk factor for depression.”
Clinical depression affects millions of American adults, and additional individuals suffer from depression that is undiagnosed or below the threshold for clinical depression (Whisman et al., 2021). Because of the strong link between depression and physical health and mortality, the authors argue that “identifying potentially modifiable causal risk factors for depression is a major priority for researchers.”
Furthermore, because approximately 50 percent of marriages end in divorce and nearly one-third of married individuals report being in a distressing relationship (Whisman et al., 2021), the intersection of relationship distress and depression affects a significant percentage of adults in the U.S. and abroad.
As the authors review, distress within intimate relationships is strongly related to a range of negative mental and physical health outcomes. If marital distress can be successfully treated, it may also have a significant impact on individuals’ mental health. Below I review the compelling evidence that the authors presented demonstrating the potential for relationship distress to cause depression.
The Methods for Studying a Causal Connection
In order to study the causal link between relationship distress and depression (variables that are usually investigated in a non-experimental fashion), the authors use “the meta-framework of triangulation…which involves synthesizing research evidence across different methodologies and study designs…to ascertain the most reliable conclusions and, ideally, increase the theoretical precision of those conclusions.”
The three research methods the authors included in this triangulation are correlational studies, genetic research, and experimental interventions targeting relationship distress. The authors point out that “relationship distress and depression may influence one another in a bidirectional fashion consistent with reciprocal causation.” Nevertheless, in this review, the authors chose to focus on the potential causal path from relationship distress to depression because relationship distress is a potentially treatable risk factor for depression.
The Ubiquity of the Correlational Relationship
As the authors review, most of the research exploring the link between relationship distress and depression is correlational in nature. These studies show that individuals who experience strong distress in their intimate relationships (such as those who endure a partner’s infidelity or other threat to leave the relationship) are also more likely to be diagnosed with depression.
A recent meta-analysis of relationship distress and depression suggests strong associations between romantic relationship distress and depression for both men and women. Moreover, this strong association is found across diverse cultures such as China, Western Europe, and Australia and across racial and ethnic backgrounds within the U.S. (see Whisman et al., 2021).
Temporal Precedence: One of the factors which researchers use to determine whether variables that are correlated might also show a causal relationship is temporal precedence. In short, for relationship distress to cause depression, relationship distress must precede the depressive symptoms. As the authors review, correlational research conducted with at least two time intervals and longitudinal research show significant relationships between baseline intimate relationship distress and future depressive symptoms.
Evidence for the temporal link between relationship distress and depression has also been found across cultures and within different types of relationships such as couples with and without children (Whisman et al., 2021). However, longitudinal research also reveals evidence for the bidirectionality of the association between relationship distress and depression, with strong links between initial depression and future relationship distress as well.
Elimination of Other Possible Causes: Another consideration when researchers investigate whether variables that are correlated might also show a causal relationship is “nonspuriousness.” Nonspuriousness refers to the researchers’ ability to eliminate other possible causes besides relationship distress which might cause depression, or factors that may cause both relationship distress and depression.
Researchers have statistically controlled for or matched samples for factors such as negative thinking, negative mood, response bias, other distressing life events, personality traits, and self-esteem. After controlling for these factors, the relationship between romantic relationship distress and depression is still statistically significant, suggesting nonspuriousness, or that other factors are not driving the association between these two variables.
Genetic Studies Point to a Causal Link
The authors review complex genetic research involving twins which further supports the causal link between relationship distress and depression. This research shows “shared genetic influences on the covariation between twins’… self-reported relationship distress…and depressive symptoms” as well as “nonshared environmental influences on the covariation between twins’ depressive symptoms and…relationship distress,” meaning that twins share a propensity for relationship distress and depression to vary together, but also that there are differences in the variation of relationship distress and depression due to being married to different partners or due to other non-genetic factors.
Importantly, in studies that statistically control for the genetic influences on the relationship between romantic relationship distress and depression, the positive correlation between romantic relationship distress and depression remains statistically significant even after adjusting for the effects of genetics on that correlational association. These findings suggest a causal relationship between relationship distress and depression over and above that which is influenced by genetics.
Moreover, studies that include responses from both individuals and their partners show that both individual feelings of romantic distress and partner feelings of romantic distress predict the individual’s depressive symptoms, suggesting that “the association between relationship distress and depression is not simply the result of having the same person evaluate both their relationship and their depression (i.e., single-reporter bias).”
Finally, the authors review evidence from experimental interventions which attempt to modify relationship distress. Research shows that various types of couples’ therapy are effective at reducing both depression and relationship distress. Furthermore, reduced levels of relationship distress during treatment are accompanied by decreases in depression after treatment. Couples’ therapy leads to reduced feelings of intimate relationship distress and depression in those couples randomly assigned to the treatment condition rather than a wait-list control condition.
One study revealed that up to “three-quarters of the treatment effect on depression was mediated by changes in relationship distress.” The authors state that “couples in treatment for relationship distress show reductions in depressive symptoms, and change in relationship distress is associated with change in depressive symptoms.” Whisman et al. conclude that “because changes in relationship distress are shown to change depression, relationship distress meets the criteria for a causal risk factor” and that “the use of couple-based interventions for preventing and reducing relationship distress has important public health implications for the prevention and treatment of depression.”
The authors note that future research should examine “the mechanisms that may lead from relationship distress to depression” including such possibilities as communication styles, suppressing thoughts and feelings, conflict resolution behaviors, social support, and attachment styles.
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Whisman, M. A., Sbarra, D. A., & Beach, S. R. (2021). Intimate relationships and depression: searching for causation in the sea of association. Annual Review of Clinical Psychology, 17, 233-258.