A recent study conducted by the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London has shed light on the relationship between depression and inflammatory proteins in adolescents. While previous research has shown a link between higher levels of cytokines, a type of inflammatory protein, and depression in adults, little was known about this connection in adolescents.
To explore this further, the researchers focused on the differences between boys and girls in terms of the inflammatory proteins associated with depression. The study, published in the Journal of Affective Disorders, revealed that boys and girls exhibited different patterns of cytokines in relation to depression risk and severity. This research was part of the IDEA (Identifying Depression Early in Adolescence) project, which received funding from MQ Mental Health Research.
The study involved 150 adolescents aged 14-16 from Brazil, equally divided into three groups: those at low risk for depression and not depressed, those at high risk for depression and not depressed, and those currently experiencing major depressive disorder (MDD). The researchers measured the levels of blood cytokines in these participants to assess inflammation.
The findings indicated that there are sex differences in the specific inflammatory proteins associated with depression in adolescents. Higher levels of the cytokine interleukin-2 (IL-2) were linked to an increased risk for depression and more severe depressive symptoms in boys, but not in girls. On the other hand, higher levels of IL-6 were associated with the severity of depression in girls, but not in boys. This suggests that IL-2 levels in boys’ blood could potentially serve as an indicator of future depression onset.
Dr. Zuzanna Zajkowska, the lead author of the study and a Postdoctoral Researcher at King’s IoPPN, commented on the significance of the findings. She emphasized that this study is the first to demonstrate differences between boys and girls in terms of the inflammation patterns associated with the risk and development of adolescent depression. Understanding these differences could contribute to the development of more targeted treatments for different biological sexes.
The researchers recruited the study participants from public schools in Brazil and assessed the risk of depression using a composite risk score based on 11 sociodemographic variables. The adolescents completed various questionnaires, self-reporting their emotional difficulties, relationships, experiences, and mood. They also underwent clinical assessments with child and adolescent psychiatrists.
Professor Valeria Mondelli, the senior author of the study and Clinical Professor of Psychoneuroimmunology at King’s IoPPN, highlighted the importance of considering the combined impact of biology, psychology, and social factors in understanding the mechanisms underlying depression. She mentioned that adolescence is a critical period for the development of mental disorders and that identifying the inflammatory proteins associated with depression and their differences between boys and girls can help shed light on this crucial time in life.
The study is part of the larger IDEA project, led by Professor Valeria Mondelli, which aims to investigate the development of depression in individuals aged 10-24 across various countries. The project explores the role of cultural, social, genetic, and environmental factors in depression development.
This research received support from MQ Mental Health Research, the UK Medical Research Council, and the Academy of Medical Sciences. Professor Valeria Mondelli is supported by the National Institute for Health and Care Research (NIHR) Maudsley Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London and the Medical Research Council.