It’s estimated that 1 in 10 U.S. adults struggle with depression¹ and another 40 million have anxiety. It’s quite common, too, for someone with depression to also have anxiety. In fact, close to half of those diagnosed with depression are also diagnosed with anxiety.²

There’s no doubt that both of these mental health conditions are at epidemic proportions, but the unanswered question remains why? Oftentimes you hear about depression or anxiety running in families, which leads to an assumption that your genetics may be to blame.

Another popular theory is that depression is due to some sort of ‘chemical imbalance’ in your brain (more on this later). But the truth is, in most cases no one really knows why some people are depressed or anxious while others are not, and most likely there are multiple factors at play.

Among them, and perhaps most important, could in fact be your life experiences, and particularly your experience of traumatic events.

Traumatic Life Events at the Root of Many Cases of Anxiety and Depression

A new study set out to determine what role familial risk, social circumstances and life events have on mental health, using surveys completed by nearly 33,000 people as their key form of data.³

They revealed that the single biggest determinant of anxiety and depression was traumatic life events, followed by to a lesser extent, family history of mental illness, income and education levels, relationship status and other social factors. According to the study’s lead author:⁴

“Whilst we know that a person’s genetics and life circumstances contribute to mental health problems, the results showed that traumatic life events are the main reason people suffer from anxiety and depression.

However, the way a person thinks about, and deals with, stressful events is as much an indicator of the level of stress and anxiety they feel.

Whilst we can’t change a person’s family history or their life experiences, it is possible to help a person to change the way they think and to teach them positive coping strategies that can mitigate and reduce stress levels.”

This is key, as it means that you are not powerless against depression and anxiety. Rather, it’s possible to modify the way you think about traumatic life events in order to minimize their impact on your mental health. Antidepressant drugs, of course, will do nothing to help in this regard.

20 Percent of Population May Have a Gene Variant Linked to Depression

Brain Derived Neurotrophic Factor (BDNF), is a key growth hormone that promotes healthy brain neurons and plays a vital role in memory. BDNF levels are critically low in people with depression, which animal models suggest may actually be a primary contributing cause.

Now researchers have determined that an alteration known as a single nucleotide polymorphism (SNP) in the BDNF gene may further contribute to the risk of anxiety, depression and memory loss. All it takes is for one ‘letter’ of BDNF’s genetic code to be ‘misspelled’ for the alteration to occur.

The SNP alteration not only decreases BDNF in neurons but also generates a protein (called Met66) that is different from the one produced by people without the alteration.

About 20 percent of the US population is thought to have the BDNF SNP that produces the Met66 protein, which, in turn, has been found to induce shrinking of neurons in the hippocampus, in areas of the brain important for memory and emotions. The shrinkage would reduce the connectivity between brain cells.

One of the study’s researchers noted:⁵

“There can be a heritable component to these diseases and it makes sense that a common variant in a gene could be involved … Just like hypertension contributes to the risk for heart disease, the BDNF alteration increases the risk of depression, anxiety and memory disorders — but is not the sole reason why they occur.”

The researchers are currently looking to develop drugs that would target Met66 or block the proteins it binds to in people with the BDNF SNP alteration. However, it would be interesting to see how natural methods that promote optimal genetic expression would work instead.

Growing evidence indicates that both fasting and exercise trigger the expression of genes and growth factors that recycle and rejuvenate your brain tissues. These growth factors include BDNF, which is known to be released in response to the stress of exercise.

BDNF activates brain stem cells to differentiate into new neurons, while also triggering numerous other chemicals that promote neural health. Perhaps it is no coincidence, then, that exercise is also one of the best-known treatments for depression.