International Study Finds a Measurable Impact of Lifestyle on Mental Illness Risk

A massive research team including University of Cambridge scholars finds evidence confirming the importance of our lifestyle in reducing mental health risk.

An international team of researchers, including scholars at the University of Cambridge and Fudan University in China, have found additional evidence that a healthy lifestyle reduces the risk of mental illness. The authors of the article published September 11, 2013, analyzed 290,000 people, 13,000 of which had depression.

Over a nine-year period, their team analyzed data from UK Biobank, a biomedical database and research resource containing anonymized data on lifestyle, genetic, and immune factors. In doing so, they identified seven healthy lifestyle patterns that were associated with lower risk of depression: moderate alcohol consumption, a healthy diet, regular physical activity, healthy sleep, frequent social connection, no smoking and avoiding sedentary behavior.

According to their analysis, a good night's sleep made the most difference of all factors. When a person regularly had between seven and nine hours sleep a night, single depressive episodes and treatment-resistant depression reduced by 22 percent, the research team concluded.

When it came to recurring depression, social connection offered the most protection, reducing risk by 18 percent.

But the most striking impacts came from combining various factors, and looking at the difference between people in groups that clustered “unfavorable,” “intermediate,” and “favorable” lifestyles:

• Those who had an "intermediate" lifestyle, meaning they adhered to most of these factors, had 41 percent less risk of developing depression.

• And those in the most favorable lifestyle group were 57 percent less likely to develop depression.

The more favorable one’s lifestyle becomes, then, the overall risk of depression decreases. The authors note a linear relationship, wherein “each one point increment in the healthy lifestyle score” was associated with measurable improvements in protections against depression.

To be sure, this doesn’t mean that lifestyle presents a simple “cure” of existing depression, nor that various lifestyle configurations represent a simple “cause” of depression.

Both of these would be oversimplifying the matter in serious ways – ignoring the role of other variables in the matter. In fact, the researchers went beyond lifestyle alone to give each participating individual a genetic risk score based on an assessment of their DNA. Those with a lower genetic risk were 25 percent less likely to develop depression when compared to those with a higher genetic risk score.

Yet that genetic contribution was significantly smaller than what came from overall lifestyle. Without denying the significant influence genetics clearly has, the authors concluded, “our study suggested that lifestyle factors may play a greater role.”

This same research team also found evidence the immune system was being influenced by these same set of lifestyle factors. For instance, high stress levels were strongly connected with the regulation of blood sugar.

Far from being purely emotional in their effects on mental health, the researchers noted ways that each lifestyle pattern had direct effects on the body - from smoking and alcohol prompting “lesions in brain circuits,” exercise prompting certain muscle secretions that improve the regulation of the hippocampus in the brain, and overeating and sedentary lifestyles “suppressing adaptive cellular stress responses.”

In a press release. Dr. Christelle Langley, 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.”

In addition to boosting brain health and cognition, she went on to underscore how these lifestyle improvements could promote better metabolism and protection against infectious disease.

The good news in this all, as the authors noted, is that so much of this is in our control - since all lifestyle factors can be understood to be “modifiable targets.”

“We can change and improve our behavior so that we have a healthy lifestyle,” the researchers note – which means that “lifestyle is something that we can act upon to reduce the risk of depression.”

Because we have a meaningful degree of control over many of these lifestyle factors, there are opportunities to make adjustments in improving them – changes that can, over time, make a measurable difference in emotional health.

While clearly providing some benefit for existing depression, it’s the preemptive effects centrally highlighted by this study. As the researchers note, “adherence to a healthy lifestyle could aid in the prevention of depression.”

This can be helpful for people of all ages, but perhaps especially for the young. "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," Professor Jianfeng Feng, from Fudan University and Warwick University, said in the same press release.