A new study has found that adopting a healthy lifestyle that includes moderate alcohol consumption, a healthy diet, regular physical activity, healthy sleep and frequent social connection, while avoiding smoking and too much sedentary behaviour, can lower the risk of depression. The study also explored the biological and psychological mechanisms that might explain this link.
The Role of Lifestyle Factors in Depression
Depression is a common mental disorder that affects around one in 20 adults worldwide. It can cause persistent sadness, loss of interest, low self-esteem, and impaired functioning. The causes of depression are complex and involve a combination of genetic, biological, psychological, and environmental factors.
To better understand how lifestyle factors influence depression risk, an international team of researchers from the University of Cambridge and Fudan University analysed data from almost 290,000 people who participated in the UK Biobank, a large-scale biomedical database and research resource. The participants were followed over a nine-year period, during which 13,000 of them developed depression.
The researchers identified seven healthy lifestyle factors that were associated with a lower risk of depression. These were:
- Moderate alcohol consumption
- Healthy diet
- Regular physical activity
- Healthy sleep
- Never smoking
- Low-to-moderate sedentary behaviour
- Frequent social connection
Of these factors, having a good night’s sleep (between seven and nine hours a night) made the biggest difference, reducing the risk of depression by 22%. Frequent social connection, which reduced the risk of depression by 18%, was the most protective against recurrent depressive disorder.
The researchers also found that the more healthy lifestyle factors an individual adhered to, the lower their risk of depression was. Individuals who followed a favourable lifestyle (five or more healthy factors) were 57% less likely to develop depression than those who followed an unfavourable lifestyle (zero or one healthy factor). This was true regardless of their genetic predisposition to depression.
The Underlying Mechanisms of Lifestyle and Depression
The researchers also investigated how lifestyle factors might affect depression risk through various biological and psychological pathways. They used data from brain scans, blood tests, and questionnaires to measure different aspects of brain structure and function, immune and metabolic systems, and personality traits.
They found that a healthier lifestyle was associated with larger volumes in brain regions involved in emotion regulation, such as the pallidum, thalamus, amygdala, and hippocampus. These regions are often smaller or less active in people with depression.
A healthier lifestyle was also associated with lower levels of inflammation and oxidative stress, which are markers of chronic stress and damage to cells and tissues. These factors can impair brain function and increase the risk of depression.
Additionally, a healthier lifestyle was associated with higher levels of extraversion and conscientiousness, which are personality traits that reflect positive emotions and goal-directed behaviour. These traits can enhance coping skills and resilience to stress and adversity.
The researchers concluded that lifestyle factors can influence depression risk by modulating various biological and psychological mechanisms that are involved in mood regulation. They suggested that lifestyle interventions could be an effective way to prevent or treat depression.
Implications and Limitations of the Study
The study is one of the first to examine the combined effects of multiple lifestyle factors on depression risk using a large-scale population-based cohort. It provides evidence that a healthy lifestyle can reduce depression risk by affecting multiple aspects of brain health and well-being.
However, the study also has some limitations. It is based on observational data, which cannot prove causality or rule out other confounding factors. It relies on self-reported measures of lifestyle factors and depression diagnosis, which may be subject to bias or error. It does not account for the quality or intensity of the lifestyle factors or their interactions with each other. It also does not address how lifestyle factors may differ in their effects depending on individual characteristics such as age, gender, ethnicity, or socioeconomic status.
Therefore, more research is needed to confirm the findings and to explore how lifestyle factors can be optimised and personalised for different groups of people at risk of depression.