Original studyBMJ Mental Health, 2026Read the paper →
How do depression and anxiety affect quality of life? A survey of more than 62,000 adults in 15 countries suggests they weigh on it almost as heavily as chronic illness. Four short questions about low mood and worry proved to be among the best guides to how people rated their own health.
Short answer: Depressive and anxiety symptoms were among the three strongest predictors of how adults rated their health, alongside the number of chronic conditions they lived with. This held in every one of the 15 countries studied. Income, education, smoking, drinking, and exercise all carried far less weight.
What the study looked at
Researchers at Oxford Brookes University, the National University of Singapore, Taylor’s University in Malaysia, and the University of Oxford analysed an international online survey carried out in 2024. The study is published in BMJ Mental Health.
The survey spanned countries including the UK, the US, Brazil, China, Germany, and Japan. Of 67,178 people who took part, 62,613 gave complete answers. Their average age was about 46, and just over half were women.
Quality of life was scored from questions on mobility, washing and dressing, usual activities, pain, and mood. The team tested 18 possible predictors, from age and income to smoking and exercise. Depression and anxiety were each measured with two quick screening questions.
How do depression and anxiety affect quality of life across countries?
The number of chronic conditions a person had was the strongest single predictor. The depression and anxiety questions came second and third, well ahead of employment status in fourth place. Income, education, money worries, physical activity, smoking, and alcohol each added very little.
The same three factors filled the top three places in all 15 countries, though their order varied. Anxiety came first in China and Japan, while depression led in Mexico and New Zealand. About one in five people screened positive for depressive symptoms, and a similar share for anxiety.
More than a matter of overlap
Because the quality of life questionnaire already asks about mood, the researchers removed the mood item and ran the analysis again. Depression and anxiety still predicted how people rated their mobility, pain, and daily activities, although their weight fell sharply, especially for anxiety.
The authors argue that health surveys with limited space should include these four questions alongside questions about physical illness. Psychreg has previously reported that loneliness raises the risk of multiple chronic illnesses.
What the study does not show
The study has clear limits. It captured a single point in time, so it cannot say whether low mood worsens physical health or the reverse. People who feel low may also rate their own health more harshly, and online panels may miss older people and the most unwell.
A model trained on 14 countries worked reasonably well when tested on the country left out, except for China. The authors say international models should be checked locally before use.
FAQ
Does anxiety affect physical health? Here, anxiety still predicted how people rated pain, mobility, and daily activities once mood was set aside, though less strongly than depression.
Do money and lifestyle matter less? For predicting quality of life in this survey, yes, though social disadvantage may act partly through illness and low mood.
