The film is about a psychologist (Marsha Mason) who works with a traumatized boy (Kiefer Sutherland) with selective mutism - the patient cannot speak in specific situations or to specific people. Eventually the boy starts to open up to reveal his sordid story.
Mitgang, Herbert (May 10, 1986). "TV: 'TRAPPED IN SILENCE' EXPLORES ELECTIVE MUTISM - The New York Times". The New York Times. Arthur Gregg Sulzberger (acceded January 1, 2018). Retrieved 2019-09-09. "Trapped in Silence" manages to tell its depressing story without being too maudlin. [… It] is all too believable as a horrible case history.
"Trapped In Silence - TV Movie - TV Tango". TV Tango. Michael Allen Vicic (CEO). May 11, 1986. Retrieved 2019-09-09. A psychologist ferrets out the reason why a sixteen year old boy suffers from elective mutism (not talking because of emotional trauma).