How to cut your risk of depression through lifestyle, according to University of Cambridge experts

Getting a good night’s sleep – between seven and nine hours a night – significantly cuts your risk of depression, say researchers.

They say a healthy lifestyle reduces your likelihood of suffering depression regardless of your genetic risk.

Examining data over a nine-year period from almost 290,000 people in the UK Biobank database – of whom 13,000 had depression – the team identify seven healthy lifestyle factors linked with a lower risk of depression, The factors - and the percentage by which they reduced the risk of single depressive episodes and treatment-resistant depression are:

- healthy sleep - 22 per cent;
- never smoking - 20 per cent;
- frequent social connection - 18 per cent;
- regular physical activity - 14 per cent;
- low-to-moderate sedentary behaviour - 13 per cent;
- moderate alcohol consumption - 11 per cent; and
- healthy diet - 6 per cent.

Frequent social connection was the most protective factor against recurrent depressive disorder, said the international team of researchers, including from the University of Cambridge and Fudan University.

They, looked at a combination of lifestyle factors, genetics, brain structure and immune and metabolic systems to identify the underlying mechanisms that might explain this link.

Based on the number of genetic variants an individual carried that have a known link to risk of depression, they found those with the lowest genetic risk score were 25 per cent less likely to develop depression when compared to those with the highest score.

But this was a much smaller impact than lifestyle.

Based on the number of healthy lifestyle factors an individual adhered to in the study, they were assigned to one of three groups: unfavourable, intermediate, and favourable lifestyle. Those in the intermediate group were about 41 per cent less likely to develop depression compared to those in the unfavourable lifestyle group, while those in the favourable lifestyle group were 57 per cent less likely.

Prof Barbara Sahakian, from the Department of Psychiatry at 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.

“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.”

MRI brain scans from nearly 33,000 participants found a number of regions where a larger volume – more neurons and connections – was linked to a healthy lifestyle, including the pallidum, thalamus, amygdala and hippocampus.

They also examined biomarkers in the blood for signs of immune system or metabolism problems. Among those found to be linked to lifestyle was the C-reactive protein - a molecule produced in the body in response to stress - and triglycerides, one of the primary forms of fat that the body uses to store energy for later.

Earlier studies have shown exposure to stress can affect how well we are able to regulate blood sugar, which may lead to a deterioration of immune function and accelerate age-related damage to cells and molecules in the body, while poor physical activity and lack of sleep can damage the body’s ability to respond to stress.

And it is known that loneliness and lack of social support increase the risk of infection and increase markers of immune deficiency.

The team, who published their findings in the journal Nature Mental Health said a poorer lifestyle impacts on our immune system and metabolism, which in turn increases our risk of depression.

Dr Christelle Langley, also from the Department of Psychiatry at 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.”

Professor Jianfeng Feng, from Fudan University and the University of Warwick, added: “We know that depression can start as early as in adolescence or young adulthood, so educating young people on the importance of a healthy lifestyle and its impact on mental health should begin in schools.”

The World Health Organization says about one in 20 adults experiences depression, which poses a significant burden on public health worldwide.