Kids with high BMI at increased risk of developing depression later in life, study suggests

Children with a high body mass index are at greater risk of depression, new research shows.

Being overweight between the ages of 12 and 16 had the biggest impact, suffering symptoms including low mood and exhaustion until their late teens.

Experts suggested body dissatisfaction and weight related stigma were leading causes and this age was a ‘crucial point’ to try and help those affected.

King’s College London, analysed data from more than 10,000 twins in the Twins Early Development Study and UK Adult Twin Registry.

They looked at the relationship between BMI and depression at ages 12, 16 and 21.

The researchers from Kings College London found being overweight between the ages of 12 and 16 had the biggest impact for depression, suffering symptoms including low mood and exhaustion until their late teens

The researchers found that children between ages 12-16 with a higher BMI were at an increased risk of developing depression than between ages 16-21.

They also found that a stronger association for children with a higher BMI at an early age to develop depression at a later age, than children with depression first to have a higher BMI later in childhood.

Dr Ellen Thompson, who led the study, said: ‘Understanding the relationship between mental ill-health and weight in adolescence is vital to provide timely support where needed.

‘This study shows a stronger association between having a higher BMI at age 12 years and subsequent depression symptoms at age 16 years than the reverse.’

Previous research found poverty may be a risk factor, however this study adjusted for socio-economic status and found the relationship between depression symptoms and weight to be unaffected.

Support structures and positive body image messages could be taught in PHSE to counteract depressive symptoms, the authors suggested as part of the findings published in Psychological Medicine.

Professor Thalia Eley, Professor of Developmental Behavioural Genetics from King’s College London, said: ‘This study shows that early adolescence is a critical point for developing depressive symptoms associated with weight gain.

‘Mental ill-health and obesity are growing concerns for Britain’s young people and this study shows how both are intertwined.

‘Working with young teens to support them to have a positive body image using strategies such as focusing on health and wellbeing rather than weight may be useful in preventing subsequent depression.’


Body mass index (BMI) is a measure of body fat based on your weight in relation to your height. 

Standard Formula:

  • BMI = (weight in pounds / (height in inches x height in inches)) x 703

Metric Formula:

  • BMI = (weight in kilograms / (height in meters x height in meters))


  • Under 18.5: Underweight
  • 18.5 – 24.9: Healthy
  • 25 – 29.9: Overweight
  • 30 – 39.9: Obese 
  • 40+: Morbidly obese