Making the correct diagnosis of depression is essential for proper treatment. Although the most common is major depressive disorder, there are other types of depression, each with its own specificities. A study published in June in the scientific journal Nature Medicine listed six subtypes of depression and anxiety, based on magnetic resonance imaging and artificial intelligence. According to the authors, the finding could be useful in aiding diagnosis and predicting the best treatment for each subtype of the disease.
Participated in the search 801 people diagnosed with depression or anxiety. They underwent functional magnetic resonance imaging – a very specific test for analyzing the activation of areas of brain structures, which is not used routinely in psychiatry. The volunteers had their brain activity evaluated at rest and during exercise for cognitive and functional analyses. They were compared with 137 healthy people (control group).
The authors focused on imaging specific brain regions known to play a role in depression. Using artificial intelligence, they were able to map six distinct patterns of brain activity in these areas.
Then, 250 random participants were given one of the three most common antidepressants used to treat the disease: escitalopram, sertraline and venlafaxine, or were referred to cognitive behavioral therapy (CBT), a psychotherapy that takes into account several aspects of the patient and how they react to certain situations. The authors wanted to see if there was a change in response to treatment according to the subtype of depression based on brain activity.
They not only found that it was, but also that the differences in the subtypes correlated with the various symptoms reported by the volunteers. “This study aims to provide a slightly more specific, more detailed differentiation to aid in the diagnosis of depression. It attempts to bring more specificities to the depressive disorder that we now call ‘major’,” says psychiatrist Daniel Oliva, from the Well-Being and Mental Health Department at Hospital Israelita Albert Einstein. “From the moment we have these specifications based on the characteristics, we can offer more accurate treatment to patients.”
How is the diagnosis made?
Depression is a problem that affects around 320 million people worldwide, according to estimates by the World Health Organization (WHO), and its diagnosis is essentially clinical. The DSM-5 (Diagnostic Manual of Mental Disorders), the main guide for psychiatric diagnoses, classifies depressive disorders into six types: major depressive disorder, which has other specificities depending on the presentation; persistent or dysthymic; disruptive mood dysregulation; premenstrual dysphoric; substance/medication-induced or disorder due to another medical condition.
“Today, to diagnose depressive disorder, we analyze the individual’s biography, reported symptoms, psychological characteristics, family history and genetic profile. Several factors are assessed to understand the psychiatric disorder itself. The presentation and combination of each of these items will guide our diagnosis to indicate the best treatment,” explains Oliva.
About 30% of patients are resistant to treatment, meaning they are unable to improve their symptoms even after at least two attempts to change medication. For up to two-thirds of people with depression, treatment fails to completely reverse symptoms to levels considered healthy.
The method of therapeutic choice today is based on trial and error, which can take months to arrive at an effective medication – hence the importance of a correct and individualized diagnosis. However, according to Oliva, there are already some pharmacogenetic tests that evaluate how the patient’s metabolism relates to medications, helping doctors in clinical practice to determine which medications to follow with a given individual.
“It is still a trial and error method, but it is not a naval battle based on luck, where we choose any medication. In addition to the scientific evidence we have for each type of disorder and the clinical experience of professionals, there are different tests, with different degrees of reliability, that already guide us towards a certain path. The proposal of this study is to offer even greater sophistication for this, identifying subtypes of depression based on the activated brain circuits”, says the psychiatrist.
In his opinion, it is essential that medicine be able to identify which brain circuit is affected by the disease in order to better understand the diagnosis, treatment and even the prognosis of depression – that is, what to expect from each subtype. “This is a vision that is being improved so that we can better understand and guide the patient. Remember that this is still a study, it is not a designation, but we are increasingly closing the circle around the best therapeutic agents that can help in the treatment of depression”, concludes Oliva.
This content was originally published in How can individualized treatment help with depression? on the CNN Brasil website.
Source: CNN Brasil
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