The proportion of adolescents with depressive symptoms has increased over the past 20 years, calling for an improved understanding of modifiable risk factors to be targeted by preventative interventions. The average BMI of children and adolescents has also increased over recent decades.
Having a high Body Mass Index (BMI) increases the risk of experiencing depressive symptoms, possibly contributing to higher levels of body dissatisfaction. Robust and long-term evidence supporting these connections is crucial for guiding preventive measures, but currently, limited strong evidence is available.
A new UCL study investigated the longitudinal associations between BMI and depressive symptoms. They found that body image concerns explain a large proportion of an association between body mass index (BMI) and depression in children, particularly in girls.
In a study with 13,135 participants from the Millennium Cohort Study, a nationally representative birth cohort study led by UCL and including people born between 2000 and 2002, scientists discovered that having a high BMI at age seven was associated with more depressive symptoms (like low mood, loss of pleasure, and poor concentration) by age 14. It was also linked to increased body dissatisfaction at age 11.
The researchers discovered that a significant portion (43%) of the connection between high BMI at age seven and later depressive symptoms was explained by body dissatisfaction. Furthermore, these associations were twice as prominent 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 longitudinal solid 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 drive 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 wellbeing.”
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 taught 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.”
Scientists noted, “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 tackle body image more effectively 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.”