Increase in the number of Young Patients with Anorexia Nervosa in Japan After the COVID-19 Pandemic

A research group led by Professor Takahiro Nemoto from the Department of Psychiatry and Neuroscience and the Department of Social Implementation Psychiatry at the Toho University Faculty of Medicine analyzed large-scale clinical data to examine the association between the COVID-19 pandemic and the incidence of anorexia nervosa (ICD-10 classification: F50.0) in young patients in Japan. Their study revealed that the number of patients with anorexia nervosa increased after the onset of the COVID-19 pandemic.
This research was published in the international academic journal Medicina (Lithuania) on March 3, 2025.

Left: Dr. Takahiro Nemoto, Right: Dr. Yoshifumi Fukuya

Key Findings

While reports from Western countries have indicated an increase in the number of young patients with anorexia nervosa after the COVID-19 pandemic, no clear evidence has been established for Japan or other Asian regions.
This study found that before the pandemic, the number of young patients with anorexia nervosa was gradually decreasing over time. However, after the onset of the pandemic, this trend reversed. Notably, this increase was more pronounced in men and younger age groups.
Similar findings have been reported in Western countries, suggesting that the COVID-19 pandemic and the subsequent lifestyle change, which is a common global phenomena beyond social and cultural differences, are strongly associated with the onset of anorexia nervosa. Additionally, factors such as an individual’s psychological states and relationships with family and friends have been suggested as potential risk factors.
Based on these findings, it is crucial to implement interventions tailored to mitigate these risk factors during future infectious disease outbreaks and major disasters to prevent the onset of anorexia nervosa, which can lead to significant social consequences.

Figure 1. Trends in newly diagnosed cases of AN aged 7–19 years. The short-dashed line indicates the period of school closure, March 2020. The dashed line shows the counterfactual trend after the COVID-19 pandemic.

Journal
Medicina (Lithuania) (March 3, 2025)

Title:
Association of COVID-19 Pandemic with Newly Diagnosed Anorexia Nervosa Among Children and Adolescents in Japan

Authors:
Yoshifumi Fukuya, Keitaro Miyamura, Tomoyuki Funatogawa, Taiju Yamaguchi, Naoyuki Katagiri, and Takahiro Nemoto* (*corresponding author)

DOI:
10.3390/medicina61030445

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