Chronic social defeat stress (CSDS), which subjects a male mouse to repeated social subordination by an aggressor male mouse, results in the onset of depression-like behaviors. CSDS in rodents is a useful model for studying the mechanisms that underlie anxiety and depression. We investigated the effect of CSDS on expression of tight junction (TJ) components in colon in C57BL/6J and BALB/c mice to address the correlation of CSDS and the development of inflammatory intestinal disease associated with epithelial barrier dysfunction. After 10 consecutive days of CSDS, BALB/c mice displayed highly social aversive behavior compared to C57BL/6J mice, which was accompanied by the suppression of intestinal Claudin-1 expression. These observations suggest that increased susceptibility to CSDS in BALB/c mice was caused by the downregulation of Claudin-1. The CSDS model with BALB/c mice is a potentially useful system for evaluating food components for psychological stress control.