Abstract:
This quasi-experimental study utilized a pretestposttest control group design.Thestudy aimed to evaluate the effects of a Happiness Enhancement Program on the stress levels of caregivers of children with developmental delays.The study was conducted over six weeks, from April to July 2025. A purposive sample of 60 caregivers was recruited from a developmental stimulation clinic at a hospital in Ubon Ratchathani province and equally assigned to either the experimental or comparison group (n=30 each). The research instruments included the Happiness Enhancement Program based on Lazarus & Folkman's framework consists of four activities and the Caregiver Stress Questionnaire. The tools were validated by three experts (CVI = 1.0), and the questionnaire yielded a Cronbach's alpha coefficient of .93. Data analysis included descriptive statistics, paired t-tests, and independent t-tests at a significance level of .05.Effect sizes were analyzed using Cohens d. The results revealed that afterreceiving the Happiness Enhancement Program, the stress levels of caregivers of children with developmental delays in the experimental group decreased significantly(p < .001).When comparing pre-and post-test results, the stress level was initially high before the intervention(X̅= 3.01, S.D.= 0.32)and decreased to a moderate level after the intervention(X̅= 2.08, S.D.= 0.25). Compared tothe comparison group, the experimental group exhibited significantly lower stress levels (X̅=2.08, S.D.= 0.24) than the comparison group (X̅= 3.19, S.D.= 0.42) at a significance level of p < .001, with a very large effect size (Cohens d = 3.78). These findings reflect the effectiveness of the HappinessEnhancement Program in reducing stress levels among caregivers of children with developmental delays compared to routine care. The program can be applied to promote caregivers mental health and enhance the efficiency of childcare.