Hyung-Jun Yoon

Background: The gut-brain axis is increasingly implicated in Alzheimer's disease (AD) pathogenesis. Objective: To investigate whether a multistrain probiotic supplement is associated with changes in AD-related plasma biomarkers and cognitive function in older adults with early cognitive impairment. Methods: In this randomized, double-blind, placebo-controlled trial, eighty-seven participants from the Gwangju Alzheimer's Disease and Related Dementias cohort were randomized to receive a multistrain probiotic (n = 40) or placebo (n = 47) for 24 weeks. Plasma phosphorylated tau 181 (pTau181), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) were evaluated at baseline and 24 weeks. Cognitive assessments included the Clinical Dementia Rating Sum of Boxes (CDR-SB), CERAD battery, Stroop test, and Rey-Osterrieth Complex Figure (ROCF). Analyses utilized linear mixed models and ANCOVA. Results: Compared to placebo, the probiotic group exhibited a significant reduction in plasma pTau181 (p < 0.001). While GFAP and NfL remained stable with probiotics, the placebo group showed significant within-group increases (p = 0.014, p = 0.041). Clinically, the probiotic group demonstrated improved CDR-SB scores (p = 0.010), primarily driven by the memory domain. Probiotics were associated with improved performance in visuospatial construction tasks (Constructional Praxis, p = 0.036; ROCF copy, p = 0.027) and preserved constructional recall, whereas the placebo group exhibited significant decline (p = 0.025). No significant between-group differences were observed in Mini-Mental State Examination, verbal memory, or executive scores. Conclusions: Multistrain probiotics modulated plasma tau and neuroinflammatory biomarkers, and selectively preserved visuospatial cognition in this study. These findings suggest the potential role of microbiota-targeted interventions as a non-pharmacological adjunct for early cognitive impairment, although further studies are required to confirm underlying mechanisms.

Objective Historical theological frameworks, particularly those rooted in Christianity, have conceptualized guilt as a defining component of melancholy. This study compared the network structures of depressive symptoms in guilt-rich and guilt-free presentations of depression using a large-scale cross-national Asian dataset.Methods We analyzed data from the Research on Asian Psychotropic Prescription Patterns for Antidepressants, Phase 3 (REAP-AD3), which included patients with depressive disorders from 11 Asian countries. Network analysis was used to estimate symptom interactions and identify the central symptoms in each group. Participants were dichotomized according to the presence or absence of prominent guilt symptoms, as determined by the “feeling bad about yourself” item of the Patient Health Questionnaire-9 (PHQ-9).Results The network structures of the two groups differed substantially. In the guilt-rich group, depressed mood was the central node that was closely linked to self-blame. By contrast, the guilt-free group exhibited centralized networks with a loss of energy.Conclusion Variations in symptom network structures can be partly explained as broadly consonant with early ideas of Richard Baxter and Robert Burton on melancholia. Clinically, symptoms related to moral judgment and self-criticism may indicate potentially different specific therapeutic attention from individuals with significant guilt. Conversely, for those without pronounced guilt, interventions targeting physical and motivational symptoms such as fatigue might inform hypothesis-driven treatment strategies.

The role of positive psychosocial factors in depression among medical students has been insufficiently studied. This study investigated the prevalence of depression and its association with positive psychosocial factors among Korean medical students. A total of 408 medical students completed a self-report questionnaire on sociodemographic characteristics, self-esteem, ego-resiliency, social support, and depression. Depressive symptoms were assessed using the Beck Depression Inventory (BDI), with scores of 16 or higher indicating the presence of depression. Fifty-five (13.5%) participants had depression. Medical students with depression showed significantly lower self-esteem, ego-resiliency, and social support than those without depression. Hierarchical regression analyses indicated that when sociodemographic factors were controlled for, self-esteem, ego-resiliency, and social support were strongly associated with lower BDI scores. Female sex and preclinical years were associated with higher BDI scores. While the findings suggest that positive psychosocial factors could play a crucial protective role against depression in medical students, the cross-sectional design limits causal inference. Longitudinal studies are required to confirm these associations.

Objectives: Mixed features in major depressive disorder (MDD)—the presence of manic symptoms during major depressive episodes (MDEs)—are associated with adverse clinical outcomes. We investigated the prevalence and clinical correlates of mixed features among Korean women with recurrent MDD. Method: Data ( n = 3000) were drawn from the Korean Mood Disorder Genetic Study‐Depression, a nationwide case‐control study recruiting women aged ≥30 years with recurrent MDD from 47 hospitals across South Korea. Structured clinical interviews assessing depressive symptoms, family history, comorbidities, and psychosocial functioning were administered. Mixed features during MDEs were defined per Diagnostic and Statistical Manual of Mental Disorders (DSM)‐5 criteria. Generalized linear models (GLMs) examined associations between mixed features and clinical correlates. Results: The worst‐MDE‐based prevalence of mixed features was 4.6%. A family history of manic episodes (odds ratio [OR] = 3.36, 95% confidence interval [CI]: 1.67–6.36) and of MDEs (OR = 1.90, 95% CI: 1.41–2.55) was significantly associated with mixed features. Five worst‐MDE symptoms were independently associated with mixed features: increased weight (OR = 2.19, 95% CI: 1.16–4.09), late insomnia (OR = 1.84, 95% CI: 1.07–3.41), slow or mixed thoughts (OR = 1.93, 95% CI: 1.18–3.33), suicidal ideation (OR = 1.96, 95% CI: 1.04–3.94), and diurnal mood variation (OR = 1.94, 95% CI: 1.34–2.81). Mixed features were associated with mood‐stabilizer use (lifetime use OR = 2.21, 95% CI: 1.38–3.42; current use OR = 2.53, 95% CI: 1.58–3.92), panic disorder (OR = 2.10, 95% CI: 1.46–2.99), premenstrual syndrome symptoms (rate ratio [RR] = 1.22, 95% CI: 1.08–1.37), and damage by suicide attempts (RR = 1.66, 95% CI: 1.17–2.07). Conclusions: Although less prevalent in this clinically ascertained sample than in Western samples, mixed features in recurrent MDD exhibit distinct clinical patterns. This finding underscores the importance of screening for mixed features, particularly when associated depressive symptoms are present, to inform early detection and treatment planning.

Lee E, et al. J Korean Med Sci. 2026 May;41:e139. https://doi.org/10.3346/jkms.2026.41.e139

Chronic somatic symptoms are hallmarks of somatic symptom disorder (SSD), characterized by notable disruptions in the day to day lives of affected patients. Risperidone is an effective augmenting agent for treatment-resistant major depressive and obsessive-compulsive disorders. Although various antidepressants have been used for the pharmacotherapy of SSDs, no guidelines have been formulated for treatment-resistant or severe SSDs. To date, the efficacy of risperidone augmentation for the treatment of antidepressant-resistant SSD has not been reported. Here, we report the case of a 68-year-old female patient with SSD and comorbid persistent depressive disorder. Upon admission, laboratory tests revealed no abnormalities except for a high triglyceride level. Psychosocial functioning and depressive symptoms were evaluated using the Global Assessment of Functioning and Beck Depression Inventory II. The severe and persistent symptoms of the patient were remarkably alleviated following low-dose risperidone augmentation with mirtazapine combined with desvenlafaxine. Furthermore, notable therapeutic effect of risperidone augmentation was observed following a significant reduction in the subjective distress of the patient and functional recovery within a short period. Our report suggests that early augmentation with risperidone facilitates the analgesic effect of serotonergic/noradrenergic antidepressants and contributes significantly to the rapid amelioration of SSD severity.

Objective Recently, burnout and mental health issues regarding nurses are reported increasingly. This study aimed to investigate the prevalence of anxiety symptoms among hospital nurses and determine their association with psychological and job-related factors.Methods Data on demographics, job-related characteristics, burnout, Type A behavior patterns, self-esteem, and happiness were collected from 515 nurses working at a university hospital in Korea. Anxiety symptoms were assessed using the anxiety subscale of the Hospital Anxiety and Depression Scale, with scores of 8 or higher indicating the presence of anxiety symptoms. Demographic, job-related, and psychological factors were compared according to the presence of anxiety. Logistic regression was conducted to identify factors associated with anxiety symptoms.Results Two hundred and four (39.6%) participants had anxiety symptoms. Self-esteem and happiness were associated with a lower risk of anxiety symptoms, whereas burnout was associated with a higher risk of anxiety symptoms. Furthermore, being female, having a career of less than five years, and requiring counseling due to stress were associated with a higher risk of anxiety symptoms. Being younger, female, or a basic nurse; having a career of less than five years; partaking in shift work; experiencing job dissatisfaction; requiring counseling due to stress; being exposed to higher levels of burnout; and having lower levels of self-esteem and happiness were all found to be significantly correlated with anxiety symptoms.Conclusion These findings suggest that promoting self-esteem and happiness while reducing burnout may be beneficial in preventing and managing anxiety symptoms among hospital nurses.

Objective This study investigated the influence of psychosocial factors on medical students’ quality of life (QOL).Methods A total of 408 medical students participated in this study. We collected data on participants’ sociodemographic details, symptoms of depression and Internet addiction, self-esteem, social support, and QOL. QOL was assessed using the World Health Organization Quality of Life-Abbreviated form, which has four domains (physical health, psychological health, social relationships, and environment). A stepwise multiple linear regression model was constructed to identify factors’ independent impact on QOL.Results Higher levels of depression and Internet addiction were associated with lower scores in all domains of QOL, whereas higher levels of self-esteem and social support were associated with higher scores. Being in third-year versus first-year was associated with higher scores in the physical health and environment domains. Living alone or in dormitories, low or middle socioeconomic status, and insufficient or moderate pocket money were associated with lower scores in the environment domain. Additionally, female students displayed significantly lower scores for physical health, psychological health, and environment than male students, but not for social relationships. There were significant differences in certain domains of QOL due to sociodemographic factors.Conclusion This study demonstrates the psychosocial factors influencing medical students’ QOL. Educational strategies focusing on strengthening self-esteem and social support as well as preventing depression and Internet addiction may contribute to improving medical students’ QOL.