Winter 2026 Research Roundup

In this Research Roundup, we provide an overview of recent research about adolescent development that highlights how the speed and timing of puberty shape brain development, how feeling economic hardship impacts youth outcomes, and the importance of mentors in lowering feelings of loneliness during the transition from adolescence to adulthood.

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In this Roundup

• How Speed and Timing of Puberty Affects Brain Development and Maturation, December 2025
• How Feeling Economic Hardship Impacts Adjustment Outcomes of Youth, October 2025
• Effects of Natural Mentoring Relationships on Late Adolescents’ Loneliness, November 2025

How Speed and Timing of Puberty Affects Brain Development and Maturation

(Pubertal Timing and Tempo Differentially Influence Cortical and Subcortical Maturation in Adolescence, Developmental Cognitive Neuroscience, December 2025)

Puberty marks the beginning of adolescence. Although puberty is a standard part of human development, the timing and speed at which we progress through puberty varies from person to person. Specifically, there are differences between adolescents in their pubertal timing (whether they reach puberty milestones earlier or later than their peers) and their pubertal tempo (whether they move through puberty more quickly or more slowly than their peers).

In this study, Clare McCann and colleagues examined how pubertal timing and pubertal tempo impact brain development during adolescence. Using data from over 6,000 adolescents in the Adolescent Brain Cognitive Development (ABCD) Study, researchers assessed pubertal development in participants yearly, beginning when participants were about 10 years old until they were about 14. The researchers also examined structural brain development every other year during that window of time. They found that adolescents who started puberty earlier than their peers also demonstrated accelerated rates of brain maturation. In particular, those who began puberty earlier on average experienced cortical thinning—a measure that, in part, reflects a normal developmental process in which the brain becomes more efficient by pruning unnecessary connections—at younger ages than their later-developing peers. Interestingly, girls who progressed through puberty more quickly than their peers showed thicker cortices than their same-aged peers, suggesting slower maturation. This suggests that faster progression through puberty does not necessarily lead to faster brain maturation, and may even reduce the speed at which certain areas of the brain develop.

Together, these findings suggest that individual differences in our experiences of puberty, including when we begin puberty and how quickly we move through the stages of puberty, play a significant role in our trajectories of brain development and maturation and affect these processes in different ways.

Why this is important: Puberty plays an important role in our brain development during adolescence. This work underlines the variations in growth and maturity in adolescence, separate from chronological age. This is one reason it is important to consider the social environment and context in which puberty is occurring—in particular, whether an adolescent is beginning puberty at a younger age or progressing through puberty at a faster rate than their peers, and whether the support and opportunities around them fit their individual needs as maturing adolescents.

How Feeling Economic Hardship Impacts Adjustment Outcomes of Youth

(Perceived economic hardship and adjustment outcomes of children and adolescents: A systematic review and meta-analysis, Journal of Research on Adolescence, October 2025)

In this meta-analysis, Luísa Ribeiro and Serap Keles examined the relationship between perceived economic hardship (such as feelings of money shortages, difficulty making ends meet, and financial worries) and adjustment outcomes in children and adolescents. They analyzed 53 studies that examined perceived economic hardship, as reported by parents or children, and its relationship to behavioral and mental health outcomes in 6- to 18-year-olds. By integrating the results across all of the studies, they identified several consistent patterns.

First, they found that greater perceived economic hardship was associated with lower self-esteem, coping, and academic achievement. They also found that perceived economic hardship was associated with higher levels of internalizing symptoms, such as depression and loneliness. This meta-analysis highlights that subjective experiences of economic strain—that is, families’ perceptions and feelings of economic hardship, beyond their objective economic status—are an important factor to consider when examining how economic circumstances can affect youth development.

Why this is important: These results suggest that programs that address the burden of feeling economic hardship may benefit youth mental health and academic achievement. For example, the researchers recommend interventions that help youth reduce feelings of shame about their economic situation, and school-based screenings to identify students who are expressing distress about their economic situations and offer informed support.

Effects of Natural Mentoring Relationships on Late Adolescents’ Loneliness

(A mixed methods study of natural mentoring relationships and loneliness in emerging adulthood, Applied Developmental Science, November 2025)

Natural mentors, defined as more experienced, non-parental adults who provide support and guidance to young people, play a significant role during the transition from adolescence to adulthood. In this study, Amy Anderson and colleagues examined the role of natural mentors in reducing feelings of loneliness during the transition from adolescence to young adulthood.

The researchers surveyed 269 college students aged 18 to 24 and asked them whether they had a natural mentor. Participants were then asked to report on the extent to which their mentors provide instrumental support (guidance or advice that helps a young person with aspects of their lives), and emotional support (space and validation to express their emotions). The researchers found that youth with natural mentors were less likely to report feelings of loneliness than those without mentors, and that the useful advice offered by mentors in particular played a role in predicting lower levels of loneliness.

The researchers then conducted interviews with 19 of the participants to better understand the importance of mentors in reducing loneliness from the perspective of youth. In these interviews, youth reported that mentors help reduce loneliness by providing practical advice, more unbiased support than other relationships, guidance in working through problems, and emotional validation.

Why this is important: The transition from adolescence to young adulthood is a period of life that can be filled with uncertainty and novel challenges. This study highlights the important role that mentors play in supporting healthy development during this transitional period of life, in part by providing tangible support that can reduce feelings of loneliness. This work suggests that programs that help youth in late adolescence connect with mentors may be effective at reducing loneliness and promoting healthy adjustment during the transition to adulthood.