Case Control Study
Copyright ©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Psychiatry. Feb 19, 2025; 15(2): 101818
Published online Feb 19, 2025. doi: 10.5498/wjp.v15.i2.101818
Immune indicators and depression in adolescents: Associations with monocytes, lymphocytes, and direct bilirubin
Jian Dai, Xiao-Tong Lin, Lu-Lu Shen, Xi-Wen Zhang, Zi-Wen Ding, Jing Wang, Xi-Wang Fan, Wei-Dong Ning
Jian Dai, Department of Clinical Psychology, Jiangbin Hospital, Nanning 530021, Guangxi Zhuang Autonomous Region, China
Xiao-Tong Lin, Lu-Lu Shen, Xi-Wen Zhang, Zi-Wen Ding, Xi-Wang Fan, Clinical Research Center for Mental Disorders, Shanghai Pudong New Area Mental Health Center, School of Medicine, Tongji University, Shanghai 200124, China
Jing Wang, Wei-Dong Ning, Department of Psychological Health, The 980th Hospital of Joint Support Force of China People's Liberation Army, Shijiazhuang 050051, Hebei Province, China
Co-first authors: Jian Dai and Xiao-Tong Lin.
Co-corresponding authors: Xi-Wang Fan and Wei-Dong Ning.
Author contributions: Dai J and Lin XT contribute equally to this study as co-first authors; Fan XW and Ning WD contribute equally to this study as co-corresponding authors; Dai J, Wang J, Fan XY, and Ning WD designed the study, methodology, and performed the research; Lin XT, Shen LL, Zhang XW, Ding ZW and Fan XY wrote and revised the manuscript; Lin XT and Shen LL revised the format; Lin XT and Zhang XW contributed to the analytic tools, software, and visualization; Dai J, Fan XY, and Ning WD contributed to the conceptualization, supervision, funding acquisition, and project administration; all the authors have read and approved the final manuscript.
Supported by the Medical Discipline Construction Project of Pudong Health Committee of Shanghai, No. PWZzb2022-09; Nanning City Science Research and Technology Development Program, No. ZC20233017; and Guangxi Medical and Health Appropriate Technology Development and Promotion Project, No. S2021061.
Institutional review board statement: The studies involving human participants were reviewed and approved by Guangxi Zhuang Autonomous Region Jiangbin Hospital Ethics Committee (Ethical Approval Number: KY-GXZR2024-01). Written informed consent to participate in this study was obtained from the participants' legal guardian or next of kin.
Informed consent statement: Both the patients and their families provided informed consent and signed a confidentiality agreement.
Conflict-of-interest statement: The authors report no relevant conflicts of interest.
Data sharing statement: The dataset used in this study is available from the corresponding author upon reasonable request.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Wei-Dong Ning, Department of Psychological Health, The 980th Hospital of Joint Support Force of China People's Liberation Army, Qiaoxi District, Shijiazhuang 050051, Hebei Province, China. ningweidong256@163.com
Received: September 28, 2024
Revised: November 4, 2024
Accepted: December 17, 2024
Published online: February 19, 2025
Processing time: 108 Days and 1.5 Hours
Abstract
BACKGROUND

Depression is a significant psychiatric disorder with particularly high prevalence among adolescents. This mental health condition can have severe consequences, including academic failure, social withdrawal, and suicidal behavior. Given the increasing rate of depression in this age group, understanding the underlying biological mechanisms is essential for early detection and intervention. Recent studies have suggested that immune markers play a role in the pathophysiology of depression, prompting further investigation of their potential association with depressive symptoms in adolescents.

AIM

To investigate the relationship between immune markers (monocytes, lymphocytes, and direct bilirubin) and the incidence and severity of depression among adolescents.

METHODS

This cross-sectional study recruited 145 adolescent patients with depression [male (M)/female (F) = 38/107] from Jiangbin Hospital in Guangxi, Zhuang and 163 healthy controls (M/F = 77/86) from routine health check-ups. Blood samples were collected after an overnight fast. Depression severity was measured using the Zung Self-Rating Depression Scale. The inclusion criteria were age 12-24 years, diagnosis of depressive disorder (ICD-10), and no recent antidepressant use. The exclusion criteria included psychiatric comorbidities and serious somatic diseases. Key statistical methods included group comparisons and correlation analyses.

RESULTS

There was a higher prevalence of females in the depression group (P < 0.001). Significant age differences were observed between the groups (Z = 9.43, P < 0.001). The depression group had higher monocyte (Z = 3.43, P < 0.001) and lymphocyte (t = 2.29, P < 0.05) counts, and higher serum direct bilirubin levels (Z = 4.72, P < 0.001). Monocyte count varied significantly according to depression severity, with lower counts in the mild group (Z = -2.90, P < 0.05). A negative correlation between age and lymphocyte counts was observed (ρ = -0.22, P < 0.01). Logistic regression analysis showed that serum direct bilirubin levels significantly predicted depression.

CONCLUSION

The potential role of elevated levels of immune markers in the early detection of depression in adolescents has been highlighted. Therefore, it is necessary to explore further the relationships between these immune markers and depression.

Keywords: Depression; Adolescents; Immune markers; Monocyte; Lymphocyte; Direct bilirubin

Core Tip: This study investigated the relationship between immune markers, specifically monocyte and lymphocyte counts and direct bilirubin levels, and depression in adolescents. By comparing 145 adolescents with depression with 163 healthy controls, we found significantly elevated levels of immune markers in patients with depression, particularly in severe cases. These findings suggest that elevated direct bilirubin levels may serve as potential immune markers for detecting depression, highlighting the importance of immune responses in understanding the mental health of adolescents.