Mind Twisting: Stress, Depression, And Intelligence

Stress and depression are two of the things in modern life that you have to deal with at one point or another. The former is an everyday thing, one that can stem from something as difficult as social anxiety to something as mundane as tripping over your own shoelaces. The latter, depression, is not quite as easy to develop in the clinical sense, but most people will end up experiencing a point in their lives that comes dangerously close to being depressed. For the most part, these two problems are considered to be threats to one's physical and mental health. However, recent studies show that these two conditions also have nasty side effects on one's intelligence.
According to recent findings, it is untrue that the human brain ceases production of neurons and other critical brain cells later on in life. In fact, there are some things that imply that the brain regenerates the aforementioned cells on an as-needed basis, generating more to suit the needs of the individual. This is in direct opposition to long-held medical doctrine that human brain cells do not regenerate after a certain point and instead begin to enter a state of slow decay. However, as recent studies have shown, the more primitive areas of the brain are capable of regenerating lost cells. This has subsequent effects on a wide range of mental functions, including memory, reaction time, and comprehension. Now, what does this have to do with stress and depression, you ask?
A whole lot, apparently. The two conditions states above put the more primitive parts of the brain into “survival mode.” Upon entering that state, the brain naturally attempts to minimize anything that could be seen as frivolous or unnecessary, instead focusing all energies on the basics. This not only accounts for the apparent reduction of brain activity during periods where an individual experiences the aforementioned problems, but it also starts to kill the currently existing cells. Basically, the brain cells are slowly dying when subjected to excessive stress and depression, burning out neurons at a faster rate than normal. This would explain why some normally intelligent people seem to be mentally slower and less adept when put under emotional and psychological pressure.
Another consequence would be the fact that the two aforementioned disorders can actually prevent the brain from regenerating new cells to replace the old ones. Trophic factors, chemicals that are known to stimulate the brain, are not produced properly when a person undergoes prolonged periods of the above conditions. Studies show that trophic factors are actually the chemicals responsible for telling the brain to regenerate new cells. If the chemicals are cut off or if the flow is disrupted, it can result in a rapid decline in the human brain's ability to repair itself over time.
While these findings are still controversial and questionable, it does provide an interesting look into just how the brain works on a physical level. The long-held belief that the brain is incapable of fixing itself once a person reaches adulthood may just be put into question. These findings are still subject to further research, but there are already several avenues being opened by the concept. For example, there are studies now being conducted devoted to finding out whether or not serotonin, a chemical used to combat a variety of mental disorders, has an effect on neuron regeneration.