Self-talk in a Patient With Down Syndrome: When is it a Concern?

Case: Thomas is a 12-year-old boy with Trisomy 21, hypothyroidism, and hearing loss. During a recent follow-up visit to the multidisciplinary Down syndrome clinic, his parents expressed concern regarding changes related to Thomas's overall functioning and increasing problematic self-talk behavior. Thomas's parents report that he has talked to "imaginary friends" (e.g., "no, don't do that" or "that's not nice") since he was in preschool. Previously, parents have been reassured that this behavior is likely externalized self-talk and have been advised to not be concerned by the behavior as it is fairly common in youth with Down syndrome.His parents shared that he has always been "in his own world," but over the past 6 months, the frequency of self-talk behavior has increased, and the content of self-talk has focused more on "bad men" (e.g., "bad men do bad things"). Thomas's parents have also noticed that it has become difficult to engage him in conversation or other tasks, including preferred activities, because of his preoccupation with "talking to imaginary friends." In addition, Thomas has begun picking at his skin to the point of bleeding, his artwork/drawings have become more rudimentary (now drawing stick figures), his sleep onset and maintenance have reduced, and he refuses to go into his bedroom because of "whispers in the walls."At school, Thomas's teachers have reported that his speech has become more difficult to understand, and he has been increasingly distracted by "talking to imaginary friends," including in the middle of class time. Classroom behavioral interventions (e.g., positive reinforcement program) have not been helpful.When asked about recent stressors, Thomas's parents shared that there was a string of car break-ins in the neighborhood around 7 months ago and have wondered if overhearing about this event could have affected Thomas in some way.Given this history, what would you consider in development of a differential diagnosis and what would be your next steps in providing care for Thomas?