Intensive Group Therapy Shows Promise for Children with Selective Mutism in Pilot Trial

Children with selective mutism often speak comfortably at home yet remain silent at school or with unfamiliar people, a pattern characteristic of the anxiety disorder in which a child fails to speak persistently in specific social situations despite speaking normally in others. A new pilot study from a German clinical sample reports that an intensive group intervention, built on principles of Parent-Child Interaction Therapy adapted for selective mutism (PCIT-SM), was associated with substantial reductions in symptom severity over the course of treatment and a three-month follow-up period.

The study enrolled sixteen children aged five to nine with selective mutism, of whom fifteen participated in the intensive group program. The researchers structured their evaluation around repeated assessments: two baseline measurements taken before treatment began, one assessment immediately after treatment, and one follow-up three months later. The primary outcome was parent-rated symptom severity measured with the Frankfurt Scale for Selective Mutism. As a secondary outcome, the team assessed remission status using a structured clinical interview, allowing them to determine whether children still met diagnostic criteria for the disorder at each point in time.

Statistical analysis relied on linear mixed-effects models to track changes across the assessment points, supplemented by Cochran’s Q tests for categorical outcomes such as diagnostic status. The results showed that symptom severity decreased significantly over time, with large effect sizes both from the first baseline to post-treatment (dRM = 1.03) and from baseline to the three-month follow-up (dRM = 1.69). Importantly, no significant differences emerged between the two baseline assessments, which strengthens the interpretation that the observed changes followed the intervention rather than reflecting ordinary fluctuation or repeated measurement effects alone.

Remission rates told a striking story. At the first baseline assessment, none of the children met criteria for remission, meaning 0% were free of the disorder. By the three-month follow-up, 47% of the children no longer met diagnostic criteria for selective mutism according to the structured clinical interview. The researchers also observed a significant overall change in diagnostic status across the assessment points. In exploratory analyses, general anxiety symptoms decreased from baseline to follow-up, suggesting that the intervention’s effects may have extended beyond speech behavior itself, although these exploratory findings require confirmation in future work.

The authors conclude that the findings provide preliminary support for intensive group interventions based on PCIT-SM principles as a promising treatment for children with selective mutism. The trial was registered retrospectively in the German Clinical Trials Register (DRKS00040917) on 13 July 2026, and the study was published as open access research in the journal Child and Adolescent Psychiatry and Mental Health on 27 October 2026. Because this was a pilot study without a control group and with a small sample of sixteen children, the results cannot establish that the treatment caused the improvements or rule out alternative explanations such as natural remission or expectancy effects. The researchers themselves emphasize that future controlled studies with larger samples and longer follow-up periods are needed to evaluate treatment mechanisms and long-term outcomes. For families affected by selective mutism, however, the study offers an encouraging early signal: an intensive, group-based approach that involves both therapists and parents in helping children practice speaking in social situations was followed by meaningful symptom improvement in nearly half of participating children three months after treatment ended.

Subject of Research: Intensive group treatment based on PCIT-SM for children with selective mutism

Article Title: Intensive group treatment for children with selective mutism: a pilot study with repeated assessments

Article References: Schwenck, C., Williams, M., Zimmermann-Hauel, J., Röse-Werkmann, C., Gehb, G., & Werkmann, N. L. (2026). Intensive group treatment for children with selective mutism: a pilot study with repeated assessments. Child and Adolescent Psychiatry and Mental Health. https://doi.org/10.1186/s13034-026-01203-4

Image Credits: AI Generated

DOI: 10.1186/s13034-026-01203-4

Keywords: selective mutism, PCIT-SM, child anxiety, pilot study, group intervention, remission, Parent-Child Interaction Therapy, Frankfurt Scale for Selective Mutism, clinical trial, mental health, Intensive, group