Study: The three subtypes of depression
The exact causes of depression are still unclear, although about 300 million people around the world suffer from mental illness. A Japanese research team came up with one more step to decipher this enigma. The researchers were able to decompose the depression in three different ways. In one of these ways, drugs do not show any effect.
A team from the Neural Computing Unit of the Institute of Sciences of Okinawa has established three types of depression that are fundamentally different. According to the researchers, the three different subtypes are largely determined by two factors. On the one hand, by certain patterns of functional connection between regions of the brain and, on the other, by traumatic childhood experiences. In one of three ways, common antidepressants show no effect. The results of the study were recently published in the scientific journal "Scientific reports".
Depression can have different bases
Selective serotonin reuptake inhibitors (ISRS) are the most commonly prescribed medication for depression that affects many patients. However, these medications do not work in the same way in all people and in some people the depression does not improve after taking it. "We have always been speculated that there are different types of depression that affect the effectiveness of the drug," says Professor Kenji Doya in a press release on the results of the study.
In his study, the researchers examined the brains of the participants. In total, patterns of brain activity in 78 different regions of the brain were analyzed using magnetic resonance imaging. In addition, the blood was examined and the subjects had to complete the questionnaires and ask to him habits of sleep, problems of stress and other mental diseases.
How are the forms of depression different?
Of the investigation, three different forms of depressive disease arose. "This is the first study to identify subtypes of depression in both life history and MRI data," explains Doya. Here are the types of depression at first glance:
- Type D1: This type of depression is characterized by a high functional connectivity of the brain. In particular, the cerebral regions responsible for the speech and number processing, spatial perception and attention have high connectivity. In addition, those affected have a history of childhood trauma.
- Type D2: This subtype is characterized by a high functional connectivity of the brain, but traumatic childhood experiences are not present.
- Type D3: In this way, only a small functional connectivity of the brain was detected and those affected did not have traumatic childhood experiences.
In which depression drugs do not show any effect
According to the research group, the group of patients who experienced childhood trauma and greater cerebral regional connectivity (type D1) underwent depression. SSRI drugs did not work. In contrast, the other two groups tend to respond positively to treatment, Japanese scientists report.
New treatment techniques are needed
According to the researchers, the study indicates the need to explore and establish new treatment techniques. Especially for those with D1 depression, new therapies should be created. "Our study provides a promising direction so that scientists study the neurobiological aspects of depression to continue their research," says Professor Doya. (VB)