New research is showing that, regardless of different environmental factors in upbringing, many children in the UK experience a “sharp” drop in their well-being early in their middle (“secondary”) school years. And a predictor of this may be their self-esteem going into secondary school.

Researchers studied 11,000 children from different parts of the UK and gathered information on their well-being at ages 11 (the start of secondary school) and three years later, when they were 14 (the end of secondary school). Researchers specifically wanted to see how these young adults felt about themselves and their home, social, and school lives. Though it’s long been understood that physical and mental well-being depends heavily on financial and familial support, this study showed that well-being declined significantly during this time, irrespective of those factors.

Experts believe the decline is due to the transition to secondary/middle school in these pre-teens. Many areas that make up emotional well-being are intrinsically linked – friends, academics, etc. – and well-being suffers when these aspects change from elementary school to middle school.

For the study, data was pulled from a more extensive study composed of young participants who all filled out questionnaires about their state of physical and emotional health. Then they were given a score of well-being based on a calculation, while the researchers made concessions for the other factors that can influence well-being (such as financial wealth and feelings of safety).

Most participants felt “satisfied” with their life at 11 but “extremely dissatisfied” at 14. At the end of the test period, almost 80% of the participants had a decline lower than the average score at the beginning. “It goes far beyond anything we would classify as moderate.”

The study did show, however, that the children who started with higher self-esteem when they were 11 did not experience as much of a decrease in well-being by the time they were 14. Meaning higher self-esteem earlier on led to better well-being later. For this reason, researchers suggest incorporating more self-esteem-boosting support in schools, such as celebrating students’ achievements and introducing positive psychology tactics.

The Children’s Society in the UK reveals that 12% of adolescents (ages 10-17) have “poor” well-being. But it’s not just the UK. The article notes that pre-teens are experiencing this type of drop in their perceived well-being worldwide.