What Brain Changes Predict Eating Disorders and Depression in Teens?

What you need to know

• Brain differences in teenagers can predict who is more likely to develop eating disorders and depression later in adolescence
• Symptoms of ADHD and conduct disorder in early adolescence increase risk for later eating disorders and depression
• Smaller brain volumes in areas involved in emotion and impulse control predict future eating disorders and depression
• These findings suggest common brain-based risk factors for both eating disorders and depression

Background

Eating disorders like anorexia nervosa, bulimia nervosa, and binge eating disorder affect up to 15% of young women and 3% of young men. They often begin in the teenage years and can have serious health consequences. Depression and anxiety also commonly occur alongside eating disorders.

To develop better ways to prevent and treat these conditions, researchers want to understand what factors in the brain and behavior might predict who is at risk before the disorders fully develop. This study looked at brain scans and behavioral assessments in a large group of European teenagers to identify early warning signs of future eating disorders and depression.

The study

The researchers followed 1,386 adolescents from age 14 to 19 as part of a large European study called IMAGEN. At age 14, the teens underwent brain scans and completed questionnaires about their mental health and behavior. The researchers then tracked which teens went on to develop disordered eating behaviors (like binge eating or purging) or depression by ages 16 or 19.

They compared the earlier brain scans and questionnaires of teens who developed these problems to those who didn’t, to see what factors might predict future risk.

Key findings

Brain differences predict future eating disorders

The study found that certain brain differences at age 14 could predict who was more likely to develop disordered eating behaviors a few years later:

• Teens who later developed binge eating had larger volumes in brain areas called the putamen and globus pallidus. These regions are involved in habitual behaviors and reward processing.

• Those who developed purging behaviors (like self-induced vomiting) had smaller volumes in parts of the prefrontal cortex. This brain region is important for controlling impulses and regulating emotions.

Similar brain differences predict depression

Interestingly, the brain differences that predicted future eating disorder behaviors also predicted who would develop depression:

• Smaller volumes in the prefrontal cortex and anterior cingulate cortex at age 14 predicted both future purging behaviors and depressive symptoms.

This overlap suggests that eating disorders and depression may have some shared brain-based risk factors.

Behavioral symptoms increase risk

The study also found that certain behavioral symptoms at age 14 predicted higher risk for later eating disorders and depression:

• Symptoms of attention-deficit/hyperactivity disorder (ADHD) predicted future purging behaviors and depression
• Conduct disorder symptoms (like aggression or rule-breaking) predicted future purging and depression
• Emotional problems predicted future binge eating

Brain differences explain the link between early symptoms and later disorders

The researchers found that the brain volume differences they observed helped explain how early ADHD and conduct disorder symptoms led to increased risk for later eating disorders and depression.

Specifically, smaller volumes in the prefrontal cortex and anterior cingulate cortex mediated the relationship between early ADHD/conduct symptoms and future purging behaviors and depression. This means the brain differences may be the mechanism through which early behavioral problems increase risk for later mental health issues.

Implications

These findings shed new light on how eating disorders and depression develop in adolescence. They suggest that there may be common brain-based risk factors that make some teens more vulnerable to both types of problems.

The results point to the importance of emotion regulation and impulse control in the development of eating disorders and depression. The brain regions identified play key roles in these functions.

Importantly, the study shows that brain and behavioral risk factors can be detected years before eating disorders or depression fully emerge. This creates opportunities for earlier identification of at-risk youth and preventive interventions.

The overlap in risk factors also suggests that treatments targeting shared mechanisms may be helpful for both eating disorders and depression. For example, interventions to improve emotion regulation and impulse control could potentially address both types of symptoms.

Limitations

There are some limitations to keep in mind:

• The study was observational, so it can’t prove that the brain differences directly caused later disorders
• The sample included very few male participants with eating disorders, so the findings may not generalize well to males
• Eating disorder symptoms were assessed by self-report only, which may be less reliable than clinical interviews

Conclusions

• Brain scans in early adolescence can help predict who is at higher risk for developing eating disorders and depression later in the teenage years
• Symptoms of ADHD and conduct disorder in early adolescence increase risk for later eating disorders and depression
• There appear to be common brain-based risk factors for both eating disorders and depression, particularly in regions involved in emotion regulation and impulse control
• These findings open up possibilities for earlier identification of at-risk youth and development of preventive interventions targeting shared risk factors