Research Progress On Obesity And Depression Link In Adolescents

About 3 million adolescents in China are obese, mainly due to changes in diet and reduced activity. The study found that obese adolescents had an increased risk of developing depression and showed lower self-efficacy, self-esteem and higher body dissatisfaction. Compared with depressed adolescents with a normal BMI, obesity was 3.5 times more likely to be depressed, and the higher the BMI, the higher the risk of depression. In addition, the higher the BMI of obese adolescents, the higher the risk of depression in adulthood. So the obesity and depression link is positive.

Depressed teens are six times more likely to be obese than their non-depressed counterparts. Depressed patients are at increased risk of obesity due to unhealthy lifestyle, imbalance of inflammatory factors and neurotransmitters. Studies have shown that some patients with depression have an increased risk of obesity due to decreased secretion of the neurotransmitter leptin, which is manifested as increased appetite, and female patients are more pronounced in early adolescence. These all prove that obesity and depression link runs both ways, and the comorbidity rate of obesity and depression is as high as 33%. Studies have found that depression is more likely to cause obesity, that is, adolescents with depression have a 3% higher risk of developing obesity than obese patients. In conclusion, analyzing the correlation between the two in adolescence and their causes may not only become an important target for the treatment of obesity and depression, but also fundamentally prevent the occurrence of both. This article will discuss the possible obesity and depression link and  mechanism from biological, psychological and social aspects.

Biological factors

1. Neuroendocrine system, inflammatory factors and leptin

Studies have shown that obesity in adolescents leads to chronic activation of the hypothalamic-pituitary-adrenal axis of the neuroendocrine system, excessive cortisol secretion leads to insufficient secretion of sex steroid hormones, and sex steroid hormone fluctuations increase the risk of depression, especially in women. The increased adipose tissue also releases some inflammatory markers, such as IL-6, TNF-α and CRP, which is consistent with the elevated inflammatory factors in the plasma of patients with depression. Moreover, the blood concentration of inflammatory factors is positively correlated with BMI, which may be a cause of increased depression risk.

2. Gut flora

The human gastrointestinal tract is home to more than 100 trillion microorganisms and weighs up to 2 kg, and adolescents are dominated by Bifidobacterium and Clostridium. Depression can lead to disturbances in the intestinal flora, such as increased levels of Bacteroides, Proteus, and Actinobacteria, and decreased levels of Firmicutes and Fika, resulting in a higher proportion of Gram-negative bacteria and a Through the increase of sexuality, bacterial endotoxins and wastes are released into the systemic circulation, and trigger an immune response, resulting in an increase in inflammatory factors such as IL-6, IL-12, and TNF-α, and the inflammatory response will trigger the accumulation of adipose tissue. cause obesity.

Social Psychological Factors

1. Campus

Obese teens are vulnerable to prejudice and unfair treatment, and are labeled as lazy, unmotivated or lacking willpower. The study found that, compared with normal-weight students, obese peers were less likely to be helped and were more likely to be bullied by their peers, with bullying lasting more than five years. This creates feelings of worthlessness and body stigma that increase the risk of depression, and students with higher levels of body stigma and depression have a higher risk of depression.This is also one of the main reasons why obesity and depression link has increased.

2. Family

Parents have a leadership role in the family, and having a parent with depression increases the risk of depression in adolescents. Adolescents have a strong ability to imitate, and they will learn their parents' methods, attitudes and ways of thinking. When one parent's cognitive model is negative, children are prone to negative thoughts such as inferiority complex and self-blame. According to surveys, parents with depression often eat unhealthy and irregular diets, and they directly provide their children with unhealthy diets, thereby increasing the risk of obesity in children.

Personal

Studies have shown that obese adolescents exhibit cognitive and executive function declines, and they are more prone to impulsiveness, such as emotional overeating. And weight-based victimization may exacerbate unhealthy eating behaviors that can lead to weight gain.

Conclusion

Clinicians need to recognize the obesity and depression link in adolescents, and use drugs with caution, because some commonly used antidepressants, such as amitriptyline and mirtazapine, are known to cause weight gain, which will reduce adolescent patients' compliance and increase the difficulty of treatment. Patients with depression and obesity can be treated with cognitive behavioral therapy to change their negative cognition.