Published: 12-12-2023 14:50 | Updated: 12-12-2023 14:57

Genetic epidemiology of depression subgroups and suicide attempts

Major Depressive Disorder (MDD) is a common mental disorder, affecting around 20% of the population worldwide. Several causes that can lead to MDD, and patients display a wide range of symptoms as well as responses to treatments. This diversity makes it challenging to pinpoint the root causes, understand the underlying mechanisms, and tailor treatments effectively. Suicide is a pressing public health concern, impacting not only individuals living with MDD but also the general population.

In her thesis from Karolinska Institutet, Thuy-Dung Nguyen, PhD student at the Department of Medical Epidemiology and Biostatistics, has investigated the genetic heterogeneity of MDD by studying clinically-informed subgroups defined from various biobank and register data sources. The thesis also provided a comprehensive epidemiological characterisation of suicide attempts by utilising the Swedish patient register. 

What are the most important results in your thesis?

“For MDD, the identification of genetic heterogeneity through subgroups and the observation of partially distinct genetic underpinnings for different clinical and psychosocial characteristics are crucial. It hopefully opens the door for personalised treatments and targeted interventions. In my studies on suicide attempts, the epidemiological characterization sheds light on the incidence and outcomes associated with suicide attempts. The familial aggregation and moderate heritability of suicide attempts emphasise the genetic component, providing a foundation for further research into the aetiology of suicidal behaviour. The identified risk factors, such as mental illnesses and adverse life events, offer valuable insights for prevention strategies.”

Why did you become interested in this topic?

“I was surprised to discover that despite the significant progress in medicine and science over the past decades, our understanding about causes and mechanism of psychiatric disorders like MDD remains limited. Living with MDD can be debilitating, often leading to increased suicide rates among those affected. Furthermore, the available treatments do not work effectively for everyone. This realization has motivated me to delve into research on the aetiology of psychiatric disorders, specifically focusing on MDD. My aim is to contribute to better managing this disorder and preventing suicide, not only within the MDD community but also among the general population.”

What do you think should be done in future research?

“My research findings suggested that different subgroups within MDD have partially unique genetic underpinnings. This result serves as a foundation for future investigations into the biology, outcomes, prognosis, and effective treatments tailored to these subgroups.”

Doctoral thesis

Genetic epidemiology of depression subgroups and suicide attempts.” 

Thuy-Dung Nguyen. Karolinska Institutet (2023), ISBN: 978-91-8017-199-1