Explainable Semi-Supervised Learning for Depression Subtype Detection in Social Media

Authors

Keywords:

Depression, Subtype Detection, Social Media, Machine Learning

Abstract

Depression detection from social-media text has been extensively studied; however, the overwhelming majority of prior research focuses on binary classification under fully supervised settings, overlooking clinically meaningful subtype distinctions and the scarcity of reliable labeled data. This study proposes a Hybrid FixMatch–Self-Training Semi-Supervised Framework for fine-grained depression subtype detection, targeting five clinically relevant categories: Major Depressive Disorder, Bipolar Depression, Psychotic Depression, Atypical Depression, and Postpartum Depression. The proposed architecture is designed to integrate supervised learning on a limited set of subtype-labeled tweets with two complementary semi-supervised mechanisms: (i) FixMatch-based consistency regularization and (ii) iterative self-training to leverage large volumes of unlabeled mental-health discourse from Twitter and Reddit. In addition, token-level explainability is planned to ensure alignment between model predictions and clinically recognized symptom patterns. In the present submission, this full architecture was evaluated as a reduced-scope, fully-reproducible proof of concept: a classical TF-IDF + linear-SVM supervised backbone combined with iterative self-training, run on CPU hardware without GPU access or connectivity to pretrained-weight repositories. Under this configuration, self-training did not outperform the purely supervised baseline (Section 3.7–4.9). Validating the full RoBERTa-encoder, FixMatch consistency branch, cross-platform robustness, and clinician-rated SHAP explainability described in Section 2 remains future work and is not claimed as completed here. By reframing subtype detection as a semi-supervised representation learning problem, this work addresses a methodological gap in computational mental-health research. The framework establishes a scalable and interpretable foundation for fine-grained digital mental-health modeling, with implications for risk screening, large-scale monitoring, and clinically informed AI systems.

Downloads

Download data is not yet available.

References

Adarsh, V., Kumar, P. A., Lavanya, V., & Gangadharan, G. R. (2023). Fair and Explainable Depression Detection in Social Media. Information Processing & Management, 60(1), 103168. https://doi.org/10.1016/j.ipm.2022.103168

Benamara, F., Moriceau, V., Mothe, J., Ramiandrisoa, F., & He, Z. (2018). Automatic Detection of Depressive Users in Social Media Conférence francophone en Recherche d'Information et Applications (CORIA),

Burdisso, S. G., Errecalde, M. L., & Montes y Gómez, M. (2021). Using Text Classification to Estimate the Depression Level of Reddit Users. Journal of Computer Science & Technology, 21. https://doi.org/10.24215/16666038.21.e1

Cha, J., Kim, S., & Park, E. (2022). A Lexicon-Based Approach to Examine Depression Detection in Social Media: The Case of Twitter and University Community. Humanities and Social Sciences Communications, 9(1), 1-10. https://doi.org/10.1057/s41599-022-01313-2

Chancellor, S., & De Choudhury, M. (2020). Methods in Predictive Techniques for Mental Health Status on Social Media: A Critical Review. NPJ Digital Medicine, 3, 43. https://doi.org/10.1038/s41746-020-0233-7

Collaborators, G. B. D. M. D. (2022). Global, Regional, and National Burden of 12 Mental Disorders in 204 Countries and Territories, 1990-2019: A Systematic Analysis for the Global Burden of Disease Study 2019. The Lancet Psychiatry, 9(2), 137-150. https://doi.org/10.1016/S2215-0366(21)00395-3

Coppersmith, G., Dredze, M., Harman, C., Hollingshead, K., & Mitchell, M. (2015). CLPsych 2015 Shared Task: Depression and PTSD on Twitter Proceedings of the 2nd Workshop on Computational Linguistics and Clinical Psychology, https://doi.org/10.3115/v1/W15-1204

Coppersmith, G., Leary, R., Crutchley, P., & Fine, A. (2018). Natural Language Processing of Social Media as Screening for Suicide Risk. Biomedical Informatics Insights, 10, 1178222618792860. https://doi.org/10.1177/1178222618792860

De Choudhury, M., Gamon, M., Counts, S., & Horvitz, E. (2013). Predicting Depression via Social Media Proceedings of the 7th International AAAI Conference on Weblogs and Social Media, https://doi.org/10.1609/icwsm.v7i1.14432

Ehghaghi, M., Rudzicz, F., & Novikova, J. (2022). Data-Driven Approach to Differentiating Between Depression and Dementia from Noisy Speech and Language Data. https://arxiv.org/abs/2210.03303

Fried, E. I., & Nesse, R. M. (2015). Depression Is Not a Consistent Syndrome: An Investigation of Unique Symptom Patterns in the STAR*D Study. Journal of affective disorders, 172, 96-102. https://doi.org/10.1016/j.jad.2014.10.010

Guntuku, S. C., Yaden, D. B., Kern, M. L., Ungar, L. H., & Eichstaedt, J. C. (2017). Detecting Depression and Mental Illness on Social Media: An Integrative Review. Current Opinion in Behavioral Sciences, 18, 43-49. https://doi.org/10.1016/j.cobeha.2017.07.005

Han, S., Mao, R., & Cambria, E. (2022). Hierarchical Attention Network for Explainable Depression Detection on Twitter Aided by Metaphor Concept Mappings. https://arxiv.org/abs/2209.07494

Harrigian, K., Aguirre, C., & Dredze, M. (2020). Do Models of Mental Health Based on Social Media Data Generalize? Findings of the Association for Computational Linguistics: EMNLP 2020, https://doi.org/10.18653/v1/2020.findings-emnlp.337

Ji, S. (2022). Suicidal Ideation and Mental Disorder Detection with Attentive Relation Networks. Neural Computing and Applications, 34(13), 10309-10319. https://doi.org/10.1007/s00521-021-06208-y

Kim, J., Ma, S. P., Chen, M. L., Galatzer-Levy, I. R., Torous, J., van Roessel, P. J., & Chen, J. H. (2025). Optimizing large language models for detecting symptoms of comorbid depression or anxiety in chronic diseases: Insights from patient messages.

LeMoult, J., & Gotlib, I. H. (2019). Depression: A Cognitive Perspective. Clinical psychology review, 69, 51-66. https://doi.org/10.1016/j.cpr.2018.06.008

Losada, D. E., & Crestani, F. (2016). A Test Collection for Research on Depression and Language Use. In International Conference of the Cross-Language Evaluation Forum for European Languages (pp. 28-39). Springer International Publishing. https://doi.org/10.1007/978-3-319-44564-9_3

Mao, L., He, R., Zhang, S., Ge, Y., Xu, E., Chen, Y., Cong, G., Miao, H., Jiang, Y., & Zhu, H. (2026). Impact of the Interaction Between Screen Time and Activity Interests on Adolescent Depression Risk: Construction of a Predictive Model Based on Machine Learning. Actas espanolas de psiquiatria, 54(2), 500-515. https://doi.org/10.62641/aep.v54i2.2068

Marriwala, N., & Chaudhary, D. (2023). A Hybrid Model for Depression Detection Employing Deep Learning. Measurement: Sensors, 25, 100587. https://doi.org/10.1016/j.measen.2022.100587

Nusrat, M. O., Shahzad, W., & Jamal, S. A. (2024). Multi Class Depression Detection Through Tweets Employing Artificial Intelligence. https://arxiv.org/abs/2404.13104

Poświata, R., & Perełkiewicz, M. (2022). OPI@ LT-EDI-ACL2022: Detecting Signs of Depression from Social Media Text Employing RoBERTa Pre-Trained Language Models Proceedings of the Second Workshop on Language Technology for Equality, Diversity and Inclusion, https://doi.org/10.18653/v1/2022.ltedi-1.40

Qudar, M. M. A., & Mago, V. (2020). TweetBERT: A Pretrained Language Representation Model for Twitter Text Analysis. https://arxiv.org/abs/2010.11091

Reavley, N., Jorm, A. F., Carbone, S., Tsiamis, E., & Morgan, A. J. (2025). Testing the Diagnostic Expansion Hypothesis With a Population-Based Survey of Attitudes to Depression in Australia. BMJ Public Health, 3(2), e003040. https://doi.org/10.1136/bmjph-2025-003040

Sohn, K., Berthelot, D., Carlini, N., Zhang, Z., Zhang, H., Raffel, C., Cubuk, E. D., Kurakin, A., & Li, C. L. (2020). FixMatch: Simplifying Semi-Supervised Learning with Consistency and Confidence Advances in Neural Information Processing Systems,

Tharaud, J. B., & Nikolas, M. A. (2025). Emotion Regulation as a Transdiagnostic Link between ADHD and Depression Symptoms: Evidence from a Network Analysis of Youth in the ABCD Study. Child and adolescent psychiatry and mental health, 19, 113. https://doi.org/10.1186/s13034-025-00966-6

Zhang, T., Schoene, A. M., Ji, S., & Ananiadou, S. (2022). Natural Language Processing Applied to Mental Illness Detection: A Narrative Review. NPJ Digital Medicine, 5(1), 1-13. https://doi.org/10.1038/s41746-022-00589-7

Downloads

Additional Files

Publication Timeline

Published
Submitted
Revised
Accepted

Issue

Section

Health Psychology

Categories

How to Cite

Nakhaei, A., Vahdat Nejad, H., & Khazaei Pour, M. (2026). Explainable Semi-Supervised Learning for Depression Subtype Detection in Social Media. KMAN Counseling & Psychology Nexus, 4, 1-18. https://journals.kmanpub.com/index.php/psychnexus/article/view/5925