A healthy lifestyle has more impact on the likelihood of developing depression than genetic makeup, according to a new study by the University of Cambridge and the University of Fudon in China.
Lifestyle choices such as getting a good night’s sleep, moderating alcohol intake, a healthy diet and an active lifestyle were found to significantly reduce the chances of developing depression by up to 57 per cent when compared to the least healthy lifestyle choices.
The new research published in Nature Mental Health shows that poor lifestyle choices impact the immune system and metabolic health, leading to an increased risk of depression, including single depressive episodes and treatment-resistant depression.
According to the World Health Organization (WHO), 1 in 20 people globally experience depression, making the illness a significant burden on public health resources.
Using data from the UK Biobank, a collection of anonymised genetic, lifestyle and health information, the researchers examined the link between lifestyle factors and depression.
They analysed the data of 290,000 people, 13,000 of whom were depressed and identified seven lifestyle factors that lower the risk of depression. These include moderate alcohol consumption, a healthy diet, regular physical activity, healthy sleep habits, never smoking, a non-sedentary lifestyle and frequent social connections.
Each participant was assigned to one of three groups based on their lifestyle choices (unfavourable, intermediate and favourable). Participants who had a favourable lifestyle were 57 per cent less likely to develop depression than those who had unfavourable lifestyles.
Getting a good night’s sleep of between seven and nine hours had the most significant impact on the rates of depression, leading to a 22 per cent reduction in the chances of developing the condition. Frequent social connection can reduce the chances of depression by 18 per cent and is the most protective lifestyle measure against recurrent depressive disorder.
Not smoking reduced the risk by 20 per cent, exercise by 14 per cent, moderate alcohol consumption by 11 per cent and a healthy diet by six per cent.
The researchers also looked at genetic predisposition to depression by examining DNA data. Based on the number of genetic variants a person had, known to be linked to depression, each participant was assigned a genetic risk score. Those with the lowest genetic risk score were 25 per cent less likely to develop depression when compared to those with the highest score, indicating a much smaller impact than lifestyle.
Professor Barbara Sahakian, from the University of Cambridge, said: ‘Although our DNA – the genetic hand we’ve been dealt – can increase our risk of depression, we’ve shown that a healthy lifestyle is potentially more important.’
She added: ‘Some of these lifestyle factors are things we have a degree control over, so trying to find ways to improve them – making sure we have a good night’s sleep and getting out to see friends, for example – could make a real difference to people’s lives.’
To understand why lifestyle can affect the chances of developing depression, the team looked at MRI scans that showed variations in parts of the brain (such as the amygdala) depending on lifestyle and blood markers, such as C-reactive protein, levels of which can be linked to an unhealthy lifestyle.
The team found that living an unhealthy life impacted the immune system and metabolism, which in turn increased the risk of depression.
Dr Christelle Langley, also from the University of Cambridge, said: ‘We’re used to thinking of a healthy lifestyle as being important to our physical health, but it’s just as important for our mental health. It’s good for our brain health and cognition, but also indirectly by promoting a healthier immune system and better metabolism.’