People often think about ways to make themselves better. Whether it’s more adaptable, kinder, or more self-confident, we turn to a variety of sources from websites that offer checklists to popular books that seem to offer magic success formulas.

But what if the answer was far more simple and straightforward? If you’re in a long-term relationship, just look to your romantic partner. If the relationship is a healthy one, chances are it’s the person who knows you the best who could be your most reliable and knowledgeable fountain of wisdom.

Long-term Relationship Effects on Depression

Looking at the situation from the opposite perspective, the latest study by University of Colorado’s Mark Whisman and colleagues (2026) builds on the vast literature suggesting that couples who don’t get along well develop symptoms of depression as the years go by. These studies became the basis for their own analysis which took a different approach to the available data.

Their first twist on the evidence was to examine not just symptoms but actual incidence of what’s called a Major Depressive Episode (MDE), or two-week period in which individuals experience diagnosable depressive symptoms. Their second twist was to use a method called “propensity score analysis” which matches groups of participants (in this case, distressed vs. non-distressed couples) on the basis of relevant controls. This can be considered random assignment “lite” in that it does everything except assign participants to groups. Its advantage over regular long-term analyses that predict depression from relationship quality is that it takes into account certain potential confounds such as personality. In this case, most importantly, neuroticism. No one has applied this to the question of how poor relationships increase depression risk.

We can use the findings from the U. Colorado study to then go back and figure out what happens when relationships flourish rather than falter, looking for ways that couples improve not only on how well they get along as a couple, but how they become happier as individuals.

Tracing the Impact of Relationships on Well-Being

Data from the University of Michigan’s Health and Retirement Study (HRS) allowed Whisman and his colleagues to trace patterns of change from the years 2014 to 2018 (they needed to avoid using data from the 2020-22 period due to COVID). The length of time for follow-up was two years.

Items assessing relationship quality included three measuring positive (e.g. How much do they really understand the way you feel about things?) and negative (How much do they criticize you?). The data also included personality assessments (e.g. neuroticism) and a scale measuring optimism. Depressive episodes were assessed by asking respondents to complete a standard MDE screening instrument and also to indicate if they had been diagnosed by a doctor (or had problems with) depression.

Women and men in the top 20% of their respective relationship distress scores were found, as predicted, to have a greater propensity of developing MDE. This predictive formula held true even when the possible confounding factors were controlled. As the authors concluded, “it is something about the relationship itself for a person in a distressed relationship that increases risk for depression, rather than characteristics of the person” (p. 7).

Why this happens can be understood, they go on to suggest, from the standpoint of the “marital discord model.” In this model, frequent and intense negative interactions detract from psychological well-being by creating spiraling patterns of stress. However, we can also see how the inverse can occur through “positive, supportive interactions” between couples.

What’s particularly impressive about this study is that, coming from the HRS, it looks not at short-term relationships, but at ones that have existed over the decades of middle and later adulthood. These people are in it for the long haul. In studies that use younger samples, it’s not possible to know what will happen in the future if/when their relationship deteriorates. They won’t be available to study after that, because they will no longer be together.

Finding Growth Through Your Relationship

To zero in on the idea of what constitutes a set of “positive supportive interactions,” think about what happens when partners go out of their way to help each other cope with life’s exigencies. Not only are they there to provide actual help when help is needed (such as managing a chronic illness) but they are there to boost each other emotionally.

In your relationship, recall the times you’ve had a tough day, making you feel hopeless and even unable to imagine how you’ll get through the next one. Did your partner try to cheer you up? Or did just enjoying simple pleasures together such as a nice dinner or a quiet night watching a movie at home help you shake off your day’s woes?

Couples in long-term relationships can also support each other through the kind of feedback they give each other, particularly feedback that is nonjudgmental and useful. Maybe that tough day was the result of your snapping at a family member or coworker, something you do once in a while without realizing it. A supportive partner won’t use this as an opportunity to point out your flaws, but instead will help walk you through ways you could be more patient and pleasant to people who upset you.

To sum up, long-term relationships can offer a way to achieve growth, not just as a couple but as an individual. The person who knows you the best may in fact be the one who helps you the most.