More creative minds are always looking for ways to explain medical phenomena. Is there an evolutionary purpose to the seeming purposelessness of the appendix, for instance? But useless organs aren't the only appropriate instance for a discussion about purpose. Some experts wonder about the evolutionary purpose of mental illnesses such as depression. Is there a good reason depression occurs?
Some experts think so. Two evolutionary psychologists believe that the purpose of depression is the enhanced mental skills that can come in tandem with this common mental illness. It seems that sadness has the effect of focusing the brain so that all attention is diverted to a specific conflict. This may provide the sufferer with the perfect tool for enhancing his ability to make good decisions.
A recent New York Times magazine article appearing under the title, Depression's Upside, says that it is the ventrolateral prefrontal cortex (VLPFC) part of the brain that is responsible for controlling what we choose as the focus of our attention. Many studies have suggested that there is an increase in blood flow to this area of the brain in patients suffering from depression. This suggests increased activity in this area of the brain. Neuroscientists in China discovered a spike in functional connectivity between this part of the brain and other areas of the depressed patient's brain. The greater the severity of the depression, the more activity is displayed in the prefrontal area of the brain.
This manifestation of hyperactivity in the VLPFC suggests that patients ruminate and are able to remain focused on their conflicts. It seems that human attention is a rare commodity. These neural effects of depression are nature's way of ensuring that this resource is given adequate and efficient allocation.
The two psychiatrists, Andrews and Thomson explain that depression and the greater activity of the VLPFC act as a "coordinated system" that was created "for the specific purpose of effectively analyzing the complex life problem that triggered the depression." They believe that if it weren't for the fact that humans react to trauma and stress with obsessive thoughts about the causal factors, they would have a reduced ability to solve their problems. The conclusion is that wisdom doesn't come for free and that it is our emotional pain that pays for this acquisition.
Some experts don't find this explanation persuasive since depression falls into many different subcategories and has an equal number of causal factors. For instance, some episodes of depression are triggered by events, while other episodes have no apparent cause yet drag on for years.