Depression, a common mental health condition that impacts various aspects of life and leads to symptoms of profound sadness and loneliness in people, is known to affect nearly 300 million people worldwide.
Results from World Mental Health surveys by the World Health Organization (WHO) and other related studies have found that depressive disorder, commonly referred to as depression, affects an estimated 3.8 percent of the global adult population. Around 4 percent of men and 6 percent of women, as well as 6 percent of adults over the age of 60 were found to experience depression.
Other figures from these studies show that more than 10 percent of pregnant women, and women who have just given birth, experience depression symptoms. And, that worldwidemore than 700 000 people die each year due to suicide, which is the fourth leading cause of death in 15–29-year-olds.
A report by the WHO also stated that although there are known, effective treatments for mental disorders, more than 75 percent of people in low- and middle-income countries have no access, or do not receive treatment. Barriers to effective care include a lack of investment in mental health care, lack of trained health-care providers and social stigma associated with mental disorders.
Given its widespread prevalence and propensity to affect anyone anywhere, pharmaceutical firms have developed several drugs to treat depressive disorders and its symptoms. A new study now shows that along with drugs and medical intervention, leading a healthy lifestyle can significantly decrease the risk of depression.
While adhering to a healthy lifestyle to avoid depression is sound common-sense, the science behind positive habits and reduced risk of depression is less well understood. The new study helps define what leading a ‘healthy lifestyle’ involves, by looking at the effects of a broad range of lifestyle factors on those affected with depression.
Previous studies have largely focused on specific lifestyle factors and their impact on depression, the new study looks at a combination of them, as well as their effects on brain structure and biomarkers.
The collaborative study, led by researchers from the University of Cambridge in the United Kingdom, concentrated on seven healthy lifestyle factors that had been identified as protective against depression. The factors were, smoking, diet, exercise level, sleep, sedentary behavior, social connectedness, and alcohol consumption
The study utilized the UK Biobank — a medical research database containing anonymous health and lifestyle information about its participants — to examine data from 287,282 participants, out of which roughly 13,000 had depression, and followed them over a nine-year period.
The study found that having a healthy lifestyle reduced the risk of depression by 57 percent. Of the seven lifestyle factors observed, healthy sleep had the greatest impact on depression risk, decreasing it by 22 percent, followed by ‘never smoking’ at 20 percent and frequent social connection at 18 percent. Having a healthy diet, consuming alcohol in moderation, regular physical activity, and reduced sedentary behavior, were also found to lower depression risk.
Based on these seven factors, participants were assigned a lifestyle score between 1 and 7 and assigned to one of three groups — unfavorable, intermediate, and favorable — indicating the overall quality of their lifestyle. Participants in the intermediate group were roughly 41 percent less likely to develop depression compared to those in the unfavorable lifestyle, while those in the favorable lifestyle group were 57 percent less likely.
Researchers also looked at genetic variants linked with depression and found that individuals with the lowest genetic risk score were 25 percent less likely to develop depression. The finding that genetic risk had a smaller impact than lifestyle, underscores that leading a healthy lifestyle can be even more important ro reducing risk of depression than genetic factors.
While the research relied on self-reporting about behaviors, which can make accuracy and consistency difficult, it also utilized biological and neurological markers to help understand the relationship between lifestyle factors and depression.
The researchers used biological markers such as triglycerides (a biomarker of increased stress), and c-reactive protein (an indicator of inflammation), as well as changes in brain structure as indicators of the biological mechanisms of depression in the body and brain.
Researchers utilized MRI brain scans of about 33,000 participants and were able to correlate healthy lifestyle factors with larger volume in certain areas of the brain, which is an indicator of brain health. The stress and inflammation biomarkers were also found to improve with lifestyle scores, highlighting the complex relationship between how stress, metabolism, and even the immune systems can affect risk for depression.
A previous study had found that high triglyceride levels were associated with increased prevalence of depression in men. Other research had associated C-reactive protein with a greater symptom severity, specific pattern of depressive symptoms, and a reduced response to treatment.
The study findings have encouraged many mental health practitioners to call for a healthy lifestyle to be included in the treatment regimen for depressive disorders. They recommend that patients build up a healthy lifestyle by choosing one of the seven lifestyle factors and to slowly build up to having all seven of them over several months until having a healthy lifestyle becomes a habit.