I've recently found information that large part of Europeans have lower than normal natural production of protein known as BDNF by brain.
BDNF induces creating new neurons in hippocampus, and as such it is required for proper functioning of memory. It is well established that insufficient level of BDNF leads to dementia.

Problems with memory may also lead to other mental health problems:

• dysfunction of memory disorganizes your daily life and in turn often leads to depression and anxiety
• inability to form new neurons in hippocampus results in being stuck with old, no longer accurate convictions – it is perceived by psychiatrists as delusions and typically diagnosed as schizophrenia (BTW most of cases of schizophrenia seem to be misdiagnoses in my opinion)

BDNF is also naturally produced by muscles while exercising on strength, so first tip to combat with depression and anxiety is to start exercising regularly (it doesn’t have to be much, just regular). Strictly speaking, white people basically have to exercise in order to keep their brains in any usable shape. From my experience it takes at least half of year to fully get back on track, it may be up to few years sometimes, however significant positive effects are visible in matter of days to weeks.

Another means of increasing BDNF are coffee and tea, however these are stimulants so they tend to amplify negative symptoms in case of anxiety in short term (however in long term are overall quite helpful).