command hallucination, a condition in which individuals hear and sometimes obey voices that command them to perform certain acts. The hallucinations may influence them to engage in behavior that is dangerous to themselves or to others. Command hallucinations can be found in schizophrenia. On some occasions, only when the commands are powerful enough, violence, including murder, may occur. It is essential for health professionals to assess for this feature of the illness. See also schizophrenia.