Total mutism--a case report of a rare psychiatric disorder and approaches for behaviour therapy.

Total mutism, which is an extremely rare psychiatric disorder, was observed in an 11-year-old boy. He refused to speak a few weeks after starting school. Behavioural analysis showed that learning by model as well as positive and negative reinforcements were involved in the pathogenesis and maintenance of the disorder. The treatment followed principles of behaviour therapy by the use of operant techniques in the sense of contingency management methods. White noise, transmitted by earphones, was utilized to interrupt auditory feedback. It has been suggested that by this method anxiety would be diminished in the case of speech phobia. Within a few months of hospital admission the boy developed speaking behaviour progressing from barely audible breaths to sibilants of normal loudness. Short dialogues were possible after 18 months. The additional conduct disorder improved simultaneously with the increase in verbal and social skills. One year after hospitalization some social uncertainty persisted with tendencies to avoid demands.