Many factors create depression

It’s fairly common knowledge that anxiety and depression are caused by psychological and environmental factors influenced to some degree by genetics. Still, no one knows how each piece of the puzzle fits together to affect the brain function and cause depressive symptoms. In an effort to answer some of those questions, a team from the Centre Emotion-Remediation et Realite Virtuelle has decided to take a closer look at the amygdala, a part of the brain that hyper-functions in people suffering from depression.

Researchers studied the impact of psychological and environmental factors combined with the genetic predisposition by looking at MRI imaging on 45 healthy individuals, including people who carry the gene predisposed to depression. They were shown all kinds of pictures and asked to indicate whether they found them pleasing or displeasing, and to think about links between the pictures and themselves thereby making a personal association. Results of the scans fell into categories based on the type of depressive gene they carried. Carriers of the short form of gene showed a higher activation of the amygdala when associating a photo with their own experience than when deciding whether an image was generally pleasing or displeasing. The opposite was true for people with the long form. So the amygdala was influenced by, not only the form of the gene, but also the type of mental activity, general or personal perception of the image.

Prior to scanning, individuals were asked to discuss stress factors occurring in their lives during the previous year. Stress also affected the influenced the activation of the amygdala.

So while the type of gene affects brain function, the influence is also modulated by both personal history and psychological condition. All of this suggests that psychotherapy, especially cognitive therapy, could have diverse cerebral effects depending on a variety of variables. It all works together on a highly individualized basis.

Source: CNRS, ScienceDaily