Because they are poor at communicating, however, if they encounter uncomfortable stimuli, interruption of persistent behavior or other setbacks, they may try to harm themselves by bumping their head or biting their hands or try to hurt those around them.
但由於這類患者缺乏與人溝通的能力，因而在遇到不舒服的刺激或固執性行為被打斷、受挫等情況下，會出現自傷行為，如撞頭、咬手等，有些也會傷及別人，多半是身旁的照顧者。