How Peer Struggles and Helping Behaviors in Childhood Shape Mental Health in Adulthood

Early peer struggles—like bullying, rejection, or social isolation—can leave lasting emotional scars.

When these difficulties persist through childhood and adolescence, they significantly increase the risk of anxiety and depression in adulthood, shaping how individuals view themselves, trust others, and cope with stress in later life.

Morneau-Vaillancourt, G., Kwong, A. S. F., Thompson, K. N., Skelton, M., Thompson, E. J., Assary, E., Lockhart, C., Oginni, O., Palaiologou, E., McGregor, T., Arseneault, L., & Eley, T. C. (2025). Peer problems and prosocial behaviours across development: Associations with anxiety and depression in emerging adulthood. Journal of Affective Disorders, 381, 360–371. https://doi.org/10.1016/j.jad.2025.04.010

Key Points

• Focus: The study explores how childhood peer problems and prosocial behaviors relate to anxiety and depression in adulthood, while accounting for genetics and shared family environment.
• Method: Researchers used a longitudinal twin and cohort study (TEDS and ALSPAC), including over 31,000 participants tracked from ages 4 to 26–28, using growth curve modeling and monozygotic twin difference analyses.
• Findings: Early and persistent peer problems increased the risk for anxiety and depression in adulthood. Surprisingly, more consistent prosocial behaviors also predicted greater mental health problems—but only before accounting for familial influences.
• Implications: Peer problems contribute uniquely to adult anxiety and depression, suggesting targeted interventions in early life. However, encouraging prosocial behavior may not be enough to prevent mental health issues.

Rationale

This study centers on two key social experiences: peer problems (e.g., rejection, bullying, conflict) and prosocial behaviors (e.g., helping, sharing, showing kindness). Both are known to influence emotional development in children and teens.

Peer problems have consistently been linked to later anxiety and depression, while prosocial behavior is generally considered protective—although some studies show mixed or even contradictory results.

What’s missing from prior research is a nuanced understanding of how these traits develop over time and affect mental health into emerging adulthood.

Many earlier studies relied on data from a single age group or informant (usually parents), lumped depression and anxiety together, or didn’t account for shared genetic and family influences.

This study fills those gaps by:

• Following children over two decades,
• Using both parent and child reports,
• Examining depression and anxiety separately (both symptoms and diagnoses), and
• Applying a twin design to account for familial (especially genetic) confounding.

This is critical for psychology because it clarifies which social behaviors might be causally linked to adult mental health and which are confounded by family background.

The findings can inform early prevention strategies and guide where interventions might be most effective.

Method

This was a longitudinal observational study using two large UK samples: the Twins Early Development Study (TEDS) and the Avon Longitudinal Study of Parents and Children (ALSPAC).

Sample

• TEDS: 19,758 twins born 1994–1996; included monozygotic (identical) pairs.
• ALSPAC: 11,258 children born 1991–1992 in Avon, England.
• Participants were assessed repeatedly from early childhood (age 4) through emerging adulthood (age 26–28).
• ~50% female; most were White British.

Variables

• Independent Variables:
  • Peer problems (e.g., social exclusion, being bullied)
  • Prosocial behaviors (e.g., helping, comforting others)
  • Both were reported by parents and children using the Strengths and Difficulties Questionnaire (SDQ) from ages 4–21.
• Dependent Variables:
  • Anxiety and depression symptoms at ages 24–28
  • Diagnosed anxiety and depressive disorders (self-reported)
  • Measured using validated tools like GAD-7, PHQ-2, sMFQ, and structured interviews (e.g., CIDI-SF, CIS-R)

Procedure

1. Recruited families in infancy and began regular follow-ups.
2. Measured peer problems and prosocial behaviors across childhood and adolescence.
3. Measured anxiety and depression symptoms and diagnoses in emerging adulthood.
4. Analyzed patterns of development using latent growth curves.
5. Conducted path analyses to explore associations with mental health.
6. Repeated analyses using monozygotic twin differences to control for genetics and shared environment.

Measures

• Strengths and Difficulties Questionnaire (SDQ)
  • Peer Problems: Assesses peer conflict, loneliness, and bullying.
  • Prosocial Behaviors: Assesses empathy, helpfulness, and cooperation.
  • Appropriate because it captures developmentally relevant behaviors across multiple time points.
• Mental Health Measures
  • Symptoms: GAD-2, PHQ-2, sMFQ, GAD-7
  • Disorders: Lifetime or current diagnosis of depression or anxiety based on self-report or diagnostic interviews
  • Reliable, validated scales sensitive to both clinical and subclinical distress.

Statistical Measures

• Researchers used latent growth curve modeling to capture each child’s developmental trajectory: their starting level of behavior (intercept) and how it changed over time (slope).
• They also used path analysis to examine how these trajectories predicted adult mental health.
• Monozygotic (MZ) twin difference models helped rule out genetic and shared environmental factors by focusing on within-pair differences.
• This approach was appropriate because it allowed the researchers to track long-term change and isolate individual (non-familial) influences.

Results

• Children with more peer problems early in life and whose problems persisted over time were at greater risk for both anxiety and depression as adults.
• These associations held across both self-reported symptoms and professional diagnoses, and in both the TEDS and ALSPAC samples.
• In contrast, prosocial behaviors were inconsistently linked to better mental health:
  • More prosocial behaviors in childhood were associated with greater anxiety and depression—especially when reported by the child.
  • These links disappeared when accounting for genetics and shared environment using MZ twins.
• Child self-reports were more predictive of adult outcomes than parent reports.
• Associations with peer problems remained even after adjusting for familial influences, suggesting a unique individual effect.
• Associations with prosocial behaviors were largely explained by family background.

Insight

This study reveals that while being kind and helpful is socially valued, it doesn’t necessarily protect children from future emotional distress.

In fact, highly prosocial children may be at risk for anxiety and depression—perhaps due to people-pleasing tendencies, over-sensitivity, or overburdening themselves emotionally.

By contrast, peer problems—particularly when persistent—are a clear, consistent risk factor for poor mental health later in life.

This highlights the long-term emotional consequences of early social adversity, like bullying or exclusion.

One particularly novel finding is that the trajectory of peer problems (how they evolve over time) is even more predictive than where a child starts.

This emphasizes the importance of not just detecting peer issues early, but monitoring and intervening as they unfold.

The monozygotic twin analyses were especially informative. They showed that:

• Peer problems predict mental health issues regardless of family background, supporting a potentially causal link.
• Prosocial behavior’s link to mental health is likely due to family or genetic influences, not a direct effect.

These findings add nuance to the idea that “being good” leads to “feeling good.” The reality appears more complex, especially in children with difficult peer relationships.

Clinical Implications

• For Schools: Early peer problems (like bullying or rejection) are strong predictors of adult mental health issues. Schools should:
  • Identify and monitor peer difficulties early.
  • Provide peer support interventions and anti-bullying programs.
  • Offer follow-up support into adolescence if problems persist.
• For Mental Health Professionals:
  • Treat peer problems as a red flag for future anxiety and depression.
  • Recognize that high prosocial behavior might not always be positive—it could signal emotional overextension or social anxiety.
• For Parents:
  • Don’t assume a “nice” or “helpful” child is emotionally well.
  • Look beneath surface behavior for signs of emotional strain, especially if the child faces peer challenges.
• Challenges:
  • It may be difficult to detect internalizing problems in children who appear well-behaved and empathetic.
  • Parents may overestimate prosocial behaviors or underestimate peer problems, so multi-informant assessments are critical.

Strengths

• Large, diverse, population-based samples (TEDS and ALSPAC)
• Longitudinal data spanning over two decades
• Use of both parent and child reports for more accurate behavior assessment
• Statistical methods that separate individual from familial effects (MZ twin design)
• Replication across two independent cohorts
• Analysis of both symptoms and diagnosed disorders

Limitations

• Participants were mostly White, limiting generalizability to more diverse populations.
• Child reports were more predictive, but this may partly reflect shared method variance (i.e., children also reported their mental health).
• Only linear growth patterns could be examined; more complex developmental changes (e.g., acceleration/deceleration) weren’t modeled due to data limitations.
• Unmeasured variables beyond familial factors could still influence findings.

Socratic Questions

1. Why might persistent peer problems, rather than one-time issues, be more predictive of later anxiety and depression?
2. How might highly prosocial behavior signal emotional vulnerability rather than resilience?
3. In what ways could parent reports differ from child self-reports—and how might this influence how we identify children at risk?
4. How do the findings challenge the assumption that “being good” always leads to better mental health outcomes?
5. What mechanisms might explain why peer problems contribute to anxiety and depression even after accounting for family background?
6. How might interventions differ if we focus on peer dynamics versus promoting kindness?
7. What are the implications of these findings for designing school-based mental health programs?
8. Can prosocial behavior ever be maladaptive? In what contexts might this be true?
9. How would the findings change if applied in a culturally or socioeconomically different population?
10. What additional variables (e.g., temperament, parenting style) might help explain these associations?