People who live a healthy lifestyle are about half as likely to develop depression as those who don’t, suggesting that lifestyle changes – such as regularly exercising and socialising – could reduce the risk of depression.

Barbara Sahakian at the University of Cambridge and her colleagues analysed data on alcohol and nicotine use, physical activity, diet, sleep and relationships among more than 280,000 adults living in the UK. Participants completed one lifestyle questionnaire between 2006 and 2010 and granted researchers access to their health records.

During the 13-year follow-up period, 12,916 participants were diagnosed with depression. Seven lifestyle factors were associated with a lower risk of developing depression after researchers adjusted for age, sex, body mass index, socioeconomic status and education. These were moderate alcohol intake, never smoking, getting enough sleep, regularly exercising, eating a healthy diet, frequently socialising and minimising sedentary behaviour.

The researchers then classified participants based on their lifestyles. People who practised five to seven of these habits had, on average, a 57 per cent lower risk of developing depression than those who adhered to less than two of the habits. Getting enough sleep, exercising and socialising had the largest influence. Each of these factors was associated with about a 20 per cent lower risk of depression.

Brain scans from a subset of participants also found an association between a higher number of healthy lifestyle habits and larger brain volume in regions known to influence mood, such as the hippocampus and prefrontal cortex. Sahakian says this suggests that lifestyle has an impact on brain biology, potentially explaining the connection between a healthy lifestyle and a lower likelihood of depression.

However, Maura Boldrini at Columbia University in New York says that depression makes it more difficult for people to find motivation to exercise and eat healthy meals. “I’m not sure that this causality effect is a one-way street,” she says.