In a new paper, published in the latest issue of the journal Proceedings of the National Academy of Sciences (PNAS), researchers argue that those people who have had a history of depression in their families are more likely to exhibit reduced volumes of brain matter on their right side. That is to say, scans reveal that this part of their brain looks very much like that of patients suffering from the Alzheimer disease. That side of the cortex is reduced by more than 28 percent, as opposed to the average levels recorded in the general population.
“The difference was so great that at first we almost didn't believe it. But we checked and re-checked all of our data, and we looked for all possible alternative explanations, and still the difference was there,” New York State Psychiatric Institute expert Dr. Bradley Peterson, who also works at the Columbia University Medical Center, explains. For the new study, the expert has scanned the brains of more than 131 people, aged 6 to 54. Some of them had a family history of depression, while the others didn't have any relatives that exhibited signs of the mental condition.
“Because previous biological studies only focused on a relatively small number of individuals who already suffered from depression, their findings were unable to tease out whether those differences represented the causes of depressive illness, or a consequence. Our findings suggest rather strongly that if you have thinning in the right hemisphere of the brain, you may be predisposed to depression and may also have some cognitive and inattention issues,” Peterson goes on to stress.
Instead of following in the footsteps of other studies, which went about analyzing depression by looking for modifications that the disease might have caused in the cortex, the new research has tried a new approach, one that has featured preemptive scans. That is to say, the expert has looked for changes in the brain that could be interpreted as clear signs that a certain person will suffer from depression at one point in their life.
In addition to the scans, Peterson has also given the participants who exhibited less developed right-side cortices memory and attention tests, which have shown that those who are at risk of suffering from depression score, on average, less than those without the risk.