Date of Submission


Degree Type


Degree Name

Doctor of Psychology (PsyD)



Department Chair

Robert A. DiThomasso, PhD, ABPP

First Advisor

James Brad Hale, PhD, Chairperson

Second Advisor

Diane Smallwood, PsyD

Third Advisor

Dr Elisa Shipon-Blum, DO


Selective Mutism (SM) is a psychiatric disorder with a relatively low incidence that impairs social communication in some settings. There are many characteristics that appear similar in some children but are absent in others. Therefore, it was hypothesized that there may be distinct SM subtypes that warrant differential diagnosis and treatment strategies. In this study, 442 Selective Mutism Comprehensive Diagnostic Questionnaires (SM-CDQ) were analyzed to help identify children with specific characteristics that made their SM unique. Participants ranged in age from 3 to18 years old and met criteria for SM. The data were coded based on 203 variables and were compared to develop profiles of SM subtypes. The variables were divided into three categories, descriptive (D), characteristics of mutism (CM), and mutism behavior ratings (MBRS). Cluster analysis of CM variables using a within-groups linkage cluster method, which is a variant of the unweighted pair group method using arithmetic averages, was used with a Phi 4-point correlation for binary data as the distance measure. An ANOVA was used with the (Mutism Behavior Rating Scale) subscales as dependent variables. Only subtypes that have more than 10 participants were included and compared on the demographic and MBRS variables. It was hypothesized that through the cluster analysis of the CM variables, subtypes would emerge.

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Psychology Commons