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How a Good Relationship Boosts Mental Health

New research on partner-driven self-expansion and mental health.

Key points

  • Personal relationships enhance our wellbeing and mental health.
  • Self-expansion through the incorporation of our partner in our own identity enhances these effects.
  • The self-expansion effect holds even when controlling for relationship length and life stressors.
Oziel Gomez / Unsplash
Source: Oziel Gomez / Unsplash

Our romantic partners play a fundamental and important role in our lives, and it is well-acknowledged that effective relationships with others improve our mental health. Having a loving partner gives us a crutch for support when we face bad times, and an outlet for finding laughter and release in times of stress.

New research, however, is showing how relationships add more. New research led by Kevin P. McIntyre, an associate professor of psychology at Trinity University in San Antonio, focuses on the role of relationship-related self-expansion on our experiences of mental health.

What is "Self-Expansion"?

Self-expansion refers to the incorporation of new information, or the augmentation of an existing positive context, into one's self-identity or self-concept. According to this model, it is often possible for people to add new skills, personality traits, and different perspectives to their existing mindset. Thinking about how this process comes about in the context of intimate relationships, McIntyre and colleagues write:

Self-expansion is thought to occur along two pathways. First, individuals can augment their self-concepts when they include aspects of a partner into their own sense of self. As partners grow closer, they may experience a cognitive merging of identities. Second, individuals can experience self-expansion via novel, challenging, and exciting shared activities with their partner, as these activities bolster individuals’ self-concepts.

Self-expansion has been linked to improved mental health, specifically in relation to negatively experiencing psychological distress and depression. This occurs because self-expansion improves levels of positive self-concept and subsequently reminds people of their growing abilities.

"According to the self-expansion model, when people enter into romantic relationships, they add positive content to their sense of self as they include aspects of their partners' identities into their own self-concept or when they complete novel activities with their partner," McIntyre explained. "For example, a person might start dating someone who volunteers at homeless shelters. As a result, they may start to view the world through the eyes of a humanitarian. As another example, a person may try new foods with their partner as they go on dates to restaurants that they have never eaten at before. Subsequently, they may start to view themselves as a 'foodie.' In both cases, these people may develop larger, positively-valenced self-concepts."

How Partner-Related Self-Expansion Helps in Depression

In the research, McIntyre's team used a variety of methods to explore the robustness of the proposed self-expansion effect. Across four studies involving more than 700 individuals and 100 couples, the research demonstrated the predicted effects, with those participants who viewed their partner as expanding their self-concept in a positive way experiencing lower levels of depressive symptoms.

When studying couples using daily diaries, the team also found that this effect was present on a day-to-day basis, and that self-expansion across a period of 14 testing days predicted depressive symptoms up to two months later. In a separate sample of people, increases in self-expansion that were related to partners were predictive of greater mental health after nine months of testing.

These effects demonstrate the apparent positive effects of partner-related self-expansion on mental health over time.

"Individuals in romantic relationships report fewer symptoms of depression when they view their relationship as a source of self-expansion," McIntyre explained. "Self-expansion seems to equip individuals with tools (in the form of positive traits, skills, and perspectives) that help them fend off psychological distress. Further, individuals in relationships that lack self-expansion may be at risk of experiencing depression symptoms."

Although the researchers focused on those who were not experiencing clinically-diagnosable levels of depression, the data do suggest that seeking out opportunities for self-expansion could have positive effects on wellbeing. Partners may thrive when they push each other out of their comfort zones and try new things.

"When we feel that our partners are helping us grow as individuals, not only do we feel closer to our partners and more satisfied with our relationship, we may be less likely to experience depression," McIntyre said.

Facebook/LinkedIn image: MAOIKO/Shutterstock


McIntyre, K. P., Mattingly, B. A., Stanton, S. C. E., Xu, X., Loving, T. J., & Lewandowski, G. W. (2022). Romantic relationships and mental health: Investigating the role of self-expansion on depression symptoms. Journal of Social and Personal Relationships.

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