Study: Three depression subtypes
The exact cause of depression is still unclear, although around 300 million people worldwide suffer from mental illness. The Japanese research team is one step closer to solving this puzzle. The researchers were able to break depression into three different forms. In one of these forms, drugs have no effect.
A team from the Neural Computing Unit at the Okinawa Institute of Science has formed three types of depression that are fundamentally different. According to the researchers, three different subtypes are largely determined by two factors. On the one hand by certain patterns of functional relationships between brain regions and on the other by traumatic childhood experiences. In one of three forms, general antidepressants have no effect. The results of the study have recently been published in the scientific journal "Scientific Reports".
Depression can have a different base
Selective Serotonin Reuptake Inhibitors (SSRIs) are the most commonly prescribed drugs for depression that affect many patients. However, these drugs do not work the same way for everyone and in some depressed people do not improve after drinking it. "It is always speculated that various types of depression exist and that they influence the effectiveness of the drug," Prof Kenji Doya said in a press release on the results of the study.
In their study, the researchers examined the brains of the participants. In total, patterns of brain activity in 78 different brain regions were analyzed using magnetic resonance imaging. In addition, blood was examined and subjects had to fill out questionnaires and were asked to sleep habits, stress problems and other mental illnesses.
How are different forms of depression?
From the study, three different forms of depression emerged. "This is the first study to identify depression subtypes from both curriculum vitae and MRI data," explained Doya. Here are the types of depression in an instant:
- Type D1: This type of depression is characterized by high functional connectivity of the brain. In particular, the region of the brain responsible for processing speech and numbers, spatial perception, and attention has high connectivity. In addition, those affected have a history of childhood trauma.
- Type D2This subtype is characterized by high functional brain connectivity, but traumatic childhood experiences do not exist.
- Type D3: In this form, only small functional connectivity of the brain can be detected and those affected do not have traumatic childhood experiences.
Where depression medication shows no effect
According to the study group, the group of patients who experienced childhood trauma and the connectivity of the higher brain region (type D1) experienced suppressed depression. SSRI drugs are not effective. In contrast, two other groups tended to respond to treatment positively, Japanese scientists reported.
New maintenance techniques are needed
As emphasized by the researchers, this study shows the need to explore and establish new treatment techniques. Especially for those who suffer from depression D1, new therapies must be created. "Our study provides promising direction for scientists who study the neurobiological aspects of depression to continue their research," Professor Doya concluded. (Vb)