Background: Social anxiety disorder (SAD) develops in the early teens and is a common disorder among university students. Understanding the predictive factors of SAD comorbid with major depressive episode (MDE) is important for student mental health care. The aim of this study was to identify the personality traits that predict SAD with MDE by analyzing longitudinal data of Japanese university students.
Methods: In this retrospective study, Japanese university students who visited the health care center of Hokkaido University for the first time were divided into the following four groups: "Control" (n = 43), "MDE" (n = 16), "SAD" (n = 28), and "SAD with MDE" (n = 61) based on the Patient Health Questionnaire-9 (PHQ-9), the Liebowitz Social Anxiety Scale, and core anxiety symptoms for SAD in the Mini International Neuropsychiatric Interview during screening. Predictors for SAD with MDE were identified by a four-group comparison of the Temperament and Character Inventory and PHQ-9 data previously obtained at the enrollment using analysis of variance and post-hoc tests.
Results: Upon comparing the four groups using analysis of variance, there were significant differences in the baseline PHQ-9 summary score, Harm-Avoidance (HA), and Self-Directedness (SD). According to results of the post-hoc test, all three showed a significant difference between the "Control" and "SAD with MDE." Furthermore, there was a significant difference in HA scores between "SAD" and "Control." In all the groups, the mean time from enrollment to the first visit to the center was >2 years.
Conclusion: A higher HA score at baseline is a predictor of SAD with or without MDE. Higher PHQ-9 summary and lower SD scores at baseline are predictive factors of SAD with MDE.