¹Daegu Catholic University School of Medicine, Psychiatry, Daegu, Korea, Republic of, ²Kyungpook National University Hospital, Psychiatry, Daegu, Korea, Republic of

Background: Pharmacological treatments for autism spectrum disorder (ASD) primarily target associated behavioral symptoms such as irritability, while core social communication deficits remain insufficiently addressed. Digital therapeutics (DTx) have emerged as scalable, non-pharmacological interventions designed to improve social functioning. NDTx-01 is a mobile-based social skills training (SST) digital therapeutic that previously demonstrated significant short-term improvements in adaptive behavior, as measured by the Korean Vineland Adaptive Behavior Scales (K-VABS), and social responsiveness, assessed by the Social Responsiveness Scale-2 (SRS-2), following a 6-week intervention. However, whether such short-term functional gains translate into sustained modification of global clinical severity beyond the active treatment phase remains unclear. Clarifying long-term trajectory effects is particularly important when considering integration of digital therapeutics within broader pharmacological and multimodal treatment strategies.

Aims & Objectives: This study aimed to evaluate the 12-month clinical trajectory of adolescents with ASD or Social Communication Disorder (SCD) following a 6-week NDTx-01 intervention, focusing on global illness severity and durability of treatment effects.

Method: A retrospective pilot analysis was conducted at Daegu Catholic University Hospital in nine adolescents aged 10–18 years diagnosed with ASD or SCD according to DSM-5 criteria. Participants were allocated to a 6-week NDTx-01 intervention group (n = 5) or a control group receiving treatment as usual (n = 4). Global clinical severity was assessed using the Clinical Global Impression–Severity (CGI-S) scale at baseline, 6 weeks (post-intervention), 6 months, and 12 months. Between-group comparisons of absolute CGI-S scores and changes from baseline were performed using Mann–Whitney U tests with exact significance due to the limited sample size. In parallel, data integration from five additional collaborating clinical centers is currently underway to enable expanded multicenter analyses.

Results: Baseline CGI-S scores did not significantly differ between groups (p = 0.730). No statistically significant between-group differences were observed in CGI-S scores at 6 weeks (p = 0.905), 6 months (p = 0.286), or 12 months (p = 0.111). Similarly, analyses of changes from baseline demonstrated no significant differences at any follow-up time point. Both groups exhibited relatively stable global clinical severity trajectories across the 12-month observation period, with no evidence of progressive divergence following discontinuation of the digital intervention.

Discussion & Conclusions: Although NDTx-01 previously demonstrated short-term improvements in adaptive and social functioning, these gains did not translate into measurable long-term modification of global clinical severity within this preliminary cohort. This finding underscores an important distinction in digital therapeutics research between domain-specific functional improvements and trajectory-level changes in overall illness severity. Short-duration digital interventions may require maintenance strategies, booster sessions, or integration with pharmacological and structured psychosocial treatments to achieve sustained clinical impact. Ongoing multicenter expansion is expected to enable adequately powered analyses to determine whether optimized digital intervention models can influence long-term clinical trajectories in adolescents with ASD.