Depression is one of the most common mental health conditions, and many people find relief through medications or therapy.
But for some individuals, even after trying different treatments, the depression doesn’t go away. This harder-to-treat type of depression is known as treatment-resistant depression, or TRD.
People with TRD often face longer and more intense symptoms, lower quality of life, and more physical health problems than those whose depression improves with standard care.
A new PhD thesis from Karolinska Institutet in Sweden sheds light on TRD. Researcher Ying Xiong from the Department of Medical Epidemiology and Biostatistics looked at the genetic and life experience factors that might cause TRD.
By combining data from health registers, genetic studies, and surveys about childhood trauma, she aimed to understand what makes some people more likely to develop this difficult condition.
One of her key findings was that TRD seems to have a stronger genetic component than other forms of depression. People with TRD were more likely to carry genetic risk factors for other serious mental illnesses, such as bipolar disorder and schizophrenia.
TRD also ran in families, along with other psychiatric and physical illnesses like anxiety, ADHD, diabetes, and heart disease. This points to a mix of shared genes and shared environments playing a role in who develops TRD.
Another major discovery was the link between childhood trauma and TRD. Even after accounting for family background, people who had experienced abuse, neglect, or other negative experiences in early life were more likely to have TRD.
This shows that early trauma can have long-lasting effects and make people more vulnerable to depression that doesn’t respond to usual treatment.
Ying Xiong’s research suggests that TRD is not just a more stubborn form of depression—it may be a separate condition, with its own causes and patterns.
Recognizing this can help doctors develop better tools to detect TRD earlier and tailor treatments to each person’s needs. For example, knowing someone’s genetic risk or history of childhood trauma might guide doctors to offer more targeted support right away instead of waiting until treatments fail.
Xiong became interested in TRD during her early research. She noticed that many patients do not get better even when several treatments are tried. She wanted to understand why this happens and how to help people who struggle with recovery. Her work combines genetics, statistics, and real-life patient data to answer those questions.
Looking ahead, she believes the future of depression care is moving toward something called precision psychiatry. This approach aims to use each person’s genetic makeup, medical history, and life experiences to choose the right treatment.
As genetic testing becomes easier and more affordable, it may one day be possible to predict who is at risk for TRD from the start—and give them the care they need sooner.
This research is important because it highlights that TRD may be more than just difficult depression—it may be its own condition. The findings show how genetics, family health history, and early life trauma all play a role in why some people don’t respond to regular treatment.
Recognizing these factors can help doctors detect TRD earlier and offer more effective care. It also shows the importance of supporting children who experience trauma, as this may reduce the risk of mental illness later in life.
If you care about depression, please read studies about how dairy foods may influence depression risk, and B vitamins could help prevent depression and anxiety.
For more information about mental health, please see recent studies that ultra-processed foods may make you feel depressed, and extra-virgin olive oil could reduce depression symptoms.
Copyright © 2025 Knowridge Science Report. All rights reserved.
