Abstract

Unmarried pregnant adolescents represent a vulnerable population facing significant psychological challenges, with their psychological well-being playing a crucial role in neonatal outcomes, maternal functioning, and long-term psychiatric resilience. However, research on psychotherapeutic interventions targeting this population remains limited. This quasi-experimental study employed a non-equivalent control group design to examine the efficacy of brief Acceptance and Commitment Therapy (ACT) in improving the psychological well-being of unmarried pregnant adolescents. A total of 24 participants aged 13–19 years were recruited from four shelter homes in Malaysia and assigned to either the brief ACT intervention group (n = 14) or the control group (n = 10). The intervention comprised three weekly online sessions, with assessments conducted at four time points: baseline, mid-intervention, post-intervention, and one-month follow-up. A Linear Mixed Model (LMM) was used to evaluate the intervention's effectiveness. The findings indicated that participants' baseline psychological well-being scores were at a borderline level (M = 51.33, SD = 26.76). The LMM analysis showed that the brief ACT intervention did not significantly improve psychological well-being over time compared with the control group. Nevertheless, descriptive findings indicated a steady increase in psychological well-being scores, reduced variability within the intervention group, and progressively larger between-group mean differences and effect sizes over time. These patterns suggest the possibility of a delayed intervention effect, although further investigation is required to establish its significance. The findings also highlight the need to consider potential ceiling effects when interpreting changes in psychological well-being scores. The study discusses its limitations and provides recommendations for future research to develop a more robust psychological intervention model for unmarried pregnant adolescents in the Malaysian context.