Nursing home patients with dementia were videotaped in three previous studies. Sixty sequences of nine patients exhibiting agitated behaviors were examined to identify the most probable antecedents to agitation. Probable reasons were interpreted and applied to the Progressively Lowered Stress Threshold model, which suggests that agitation is stress related. Analysis suggests that agitation often serves as form of communication. Two underlying reasons seem to be that the patient had loss of control over the situation and deficient autonomy. The most common causes for expressed agitation were interpreted as discomfort, a wish to be served immediately, conflict between patients or with nursing staff, reactions to environmental noises or sound, and invasion of personal space. It is recommended that nursing staff promote autonomy and independency for this group of patients whenever possible. By evaluating probable reasons for expressed agitation, the nursing staff can take steps to prevent or alleviate agitation.