A new study, published on Monday (17) in the journal Nature Medicine, classified depression into six biological types (or “biotypes”) based on brain imaging combined with machine learning. The discovery could help define the best treatments for the condition in the future.
O work was carried out to discover how doctors and mental health specialists can be more accurate in treating depression with their patients. About 30% of people with depression have a condition called “treatment-resistant depression,” which means that different types of medications or therapies have not been able to improve the symptoms of the disorder.
According to the researchers, this happens, in part, because there is still no efficient way to know which antidepressant or type of therapy could help an individual patient. Medications are often prescribed through a “trial and error” method, so it can take months or years to find a medication that fully works.
“The goal of our work is to figure out how we can get it right the first time,” says Leanne Williams, director of the Center for Mental Health and Wellbeing at Stanford Medicine, in the United States, in press release. “It’s very frustrating to be in the depression field and not have a better alternative to this unique approach.”
To carry out the study, researchers evaluated 801 patients who were previously diagnosed with depression or anxiety, using functional magnetic resonance imaging (or fMRI) imaging tests to measure brain activity. They examined participants’ brains at rest and when they were engaged in different tasks designed to test cognitive and emotional functioning.
Next, the researchers used a machine learning approach called “cluster analysis” to group the patients’ brain images together. From this, it was possible to identify six distinct patterns of activity in the brain regions analyzed.
Different treatments for each type of depression
After identifying the different biotypes of depression, scientists randomly assigned 250 study participants to receive one of the three most commonly used antidepressants in treatment. Patients who presented with a disease pattern characterized by hyperactivity in the cognitive regions of the brain experienced the best response to the antidepressant venlafaxine (popularly known as Effexor), compared to other biotypes.
People who showed a pattern whose brains at rest had higher levels of activity among three regions associated with depression and problem solving were able to achieve greater symptom relief with behavioral psychotherapy.
Finally, those with a third subtype, characterized by lower levels of resting activity in the brain circuit that controls attention, were less likely to see improvement in symptoms with psychotherapy compared to those with other patterns of depression.
According to Jun Ma, professor of medicine at the University of Illinois, in Chicago, in the United States, and one of the study’s authors, the type of therapy used in the study teaches patients skills to better deal with daily issues, so that those who have high levels of activity in these brain regions may more readily adopt these new skills.
As for those with less brain activity associated with attention and engagement, it is possible that pharmaceutical treatment could help these patients obtain more benefits from psychotherapy.
“To our knowledge, this is the first time we have been able to demonstrate that depression can be explained by different disturbances in brain function,” explains Williams. “In essence, it is a demonstration of a personalized medicine approach to mental health based on objective measures of brain function.”
Differences in symptoms
The study also found that different types of depression correlate with differences in symptoms and task performance. Those with overactive cognitive regions in the brain have more difficulty feeling pleasure than the rest of the participants. They also performed worse on executive function tasks.
The subtype that responded best to psychotherapy made more errors on executive function tasks, but performed well on cognitive tasks.
On the other hand, one of the six types found in the study did not show noticeable differences in brain activity in the regions photographed in relation to the activity of people without depression.
Now, the research team is expanding the imaging study to include more participants and test more treatment options for all six depression biotypes, including medications not traditionally used for the disease.
“To really advance the field toward precision psychiatry, we need to identify the treatments that are most likely to be effective for patients and get them into that treatment as quickly as possible,” says Ma. “Having information about brain function, in particularly the validated signatures we evaluated in this study, would help inform more accurate treatments and prescriptions for individuals”, he concludes.
Source: CNN Brasil
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