Body dissatisfaction at age 11 is linked to increased risk of depression by age 14, finds a new longitudinal study led by UCL researchers.

The findings, published in The Lancet Psychiatry, show that body image concerns explain a large proportion of an association between body mass index (BMI) and depression in children, particularly in girls.

The study involved 13,135 participants of the Millennium Cohort Study, a UCL-led nationally representative birth cohort study of people born between 2000 and 2002.

The researchers found that high BMI at age seven was linked with increased depressive symptoms (which can include low mood, loss of pleasure and poor concentration) by age 14, as well as with greater body dissatisfaction at age 11.

They found that body dissatisfaction was a major contributor to the link between BMI at age seven and subsequent depressive symptoms, explaining 43% of the association.

All three of these associations were twice as large in girls compared to boys.

Lead author Dr. Francesca Solmi (UCL Psychiatry) said, "Depression has become more common among young people, as have having an overweight BMI, and body dissatisfaction. Here we have found strong longitudinal evidence that a high BMI in childhood is linked with an increased risk of depressive symptoms multiple years later.

"But we were particularly interested in how much body dissatisfaction might be the driver of this link. We found strong evidence that being unhappy with one's appearance is linked with increased depressive symptoms years later. Our findings suggest that any efforts to reduce weight in childhood need to consider their potential mental health impacts, so that we can avoid stigmatizing weight and instead support children's mental health and well-being."

The research did not cover what other factors, besides body dissatisfaction, could explain why children with high BMI are more likely to develop depressive symptoms, but they say that other biological (for instance inflammation) or environmental (for instance bullying) pathways might explain part of the association.

First author Emma Blundell, trainee clinical psychologist at UCL Psychology & Language Sciences, said, "Many public health strategies seek to reduce weight in childhood. Primary school children are being taught about the importance of calories and exercise, and all young people in England are being weighed at school to determine whether weight loss efforts are needed. While promoting healthy diet and exercise is important, it may be that some public health messaging could be fostering feelings of guilt or shame. It is important to ensure that any interventions to reduce BMI in childhood do not inadvertently increase body dissatisfaction and harm children's mental health."

The researchers say that some strategies to target body image concerns in early adolescence have been developed, such as with psychological interventions or media literacy training that could address self-esteem, social comparisons, and social media influences, but more research is needed to more effectively tackle body image concerns in young people.

Dr. Solmi added, "Reducing body dissatisfaction in young people could be an important way of preventing depression, particularly in girls, at ages when social environments and peer relations become increasingly impactful."

The study additionally involved researchers in the UCL Great Ormond Street Institute of Child Health, the UCL Institute of Epidemiology & Health Care, MRC Unit for Lifelong Health & Ageing at UCL, and Imperial College London. The Millennium Cohort Study is based at the UCL Centre for Longitudinal Studies, in the IOE, UCL's Faculty of Education & Society.