Examining a novel, parent child interaction therapy-informed, behavioral treatment of selective mutism.

BACKGROUND

The purpose of this study was to evaluate a new therapy for children with selective mutism (SM) that combines Parent-Child Interaction Therapy principles and behavioral techniques.

METHOD: Children aged 4-10 with a primary diagnosis of SM were eligible to participate. Comorbidity was allowed with the exception of autism spectrum disorder, intellectual disability, mania or psychosis. Of 54 potentially eligible participants, 33 met inclusion/exclusion criteria of which 31 families consented (94%). Following assessment, children were waitlisted for an average of 4 months before receiving 16 sessions of weekly therapy at an outpatient psychiatry clinic of a children's hospital in Vancouver, Canada; all children completed treatment. Assessments were conducted at time of referral (baseline), pre-treatment, post-treatment, 3 month follow up, and 1 year follow up. Two did not complete follow up assessments (93% retention).

RESULTS

Results showed significant and large (Cohen's d = 1.80) gains in speaking behaviors across contexts from pre- to post-treatment. Gains were maintained at 3-months and 1-year post-treatment. Statistically significant and large improvements were also found in post-treatment teacher and parent reports of child anxiety as well as a behavioral measure of the child speaking to an unknown adult. Parents reported high satisfaction with treatment. None of the potential predictors of treatment response examined were found to be significant.

CONCLUSIONS

PCIT-SM appears to be an effective treatment for children aged 4-10 with SM.