Identity develops well into adulthood and is linked to better mental well-being

The Jyväskylä Longitudinal Study of Personality and Social Development from the University of Jyväskylä examined the average development of identity and mental well-being in adulthood, as well as the links between them. Identity was assessed when the same individuals were aged 27, 36, 42, 50, and 61, and mental well-being was assessed when they were aged 36, 42, 50, and 61. 

Identity develops through exploration and commitment 

Identity refers to individuals' views of themselves and the things they consider important in different areas of life. It provides individuals with a sense of continuity across time. In this study, identity development was assessed based on how strongly individuals were committed to these views and whether they had been formed through personal exploration or adopted from significant others or society more broadly. 

A well-developed identity is characterized by clear views to which individuals have committed through personal exploration. 

Identity continues to develop throughout adulthood 

Identity development is often viewed as a phenomenon of adolescence. This is partly due to the scarcity of studies that have examined identity across adulthood.  

“Our study showed that identity can continue to develop throughout adulthood. The results indicated positive identity development between ages 27 and 61, with the most changes occurring between ages 27 and 42,” says doctoral researcher Liinu Marin from the University of Jyväskylä. 

Identity and mental well-being are linked 

In addition, the study investigated how identity was associated with mental well-being. Mental well-being was assessed through psychological and social well-being, life satisfaction, and feelings of anxiety and depression. Psychological well-being encompasses aspects such as autonomy and a sense of purpose in life, whereas social well-being includes, for example, feelings of connectedness in communities and society. 

“The study showed that a more positively developed identity was associated with better mental well-being. This was evident, for example, in better psychological and social well-being and fewer feelings of anxiety,” Marin says. 

However, the study did not examine the causal direction of these associations. 

“Mental well-being may also support or challenge the formation of identity. Nevertheless, the findings suggest that identity and mental well-being are linked in adulthood,” Marin explains. 

The study is part of the Jyväskylä Longitudinal Study of Personality and Social Development (JYLS), which has followed the development of the same individuals for more than 50 years. The study was led by Professor Lea Pulkkinen from 1968 to 2012 and has been led by Research Director Katja Kokko since 2013. Today, the JYLS is conducted at the Gerontology Research Center within the Faculty of Sport and Health Sciences at the University of Jyväskylä. The study was primarily funded by the Research Council of Finland. 

Original article: 

Marin, L., Fadjukoff, P., Kekäläinen, T., Tolvanen, A. & Kokko, K. (2026). Development of Overall Identity and Mental Well-Being and Their Associations in Adulthood. Journal of Adult Development. https://doi.org/10.1007/s10804-026-09572-y