Lactobacillus-containing Cultured Milk Drink Alleviates Depression Score Among Adults With Irritable Bowel Syndrome

A total of 140 subjects who fulfilled Rome IV criteria for IBS will be recruited from a tertiary medical centre and among public volunteers. The depression status and categories will be assessed using the Centre Epidemiologic Studies Depression Scale Revised questionnaire (CESD-R): normal mood (score\<16), or subthreshold depression (score\>16). The subjects are randomised and blinded into four groups: Group A (Normal mood with placebo, n=35), Group B (Normal mood with probiotics, n=35), Group C (Subthreshold depression with placebo, n=35) and Group D (Subthreshold depression with probiotics, n=35). The subjects will be instructed to consume two bottles of cultured milk drink daily for 12 weeks. The probiotic cultured milk drinks contained 10\^9 cfu L. CASEI-01 and LA-5. The severity of depression will be measured using Patient Health Questionnaire (PHQ-9) at pre- and post-12-week intervention. Secondary outcome on IBS symptoms severity will be assessed with IBS Symptoms Severity Score (IBS-SSS) and IBS Quality of Life (IBS-QOL).