The diagnosis of mental illness is becoming more prevalent in the United States.With the increased identification, it is imperative that health care professionals are astute in identifying mental health conditions and behaviors associated with those conditions.The most common use of pro re nata (PRN) or "as needed" psychoactive medications in the inpatient psychiatric setting is for the reduction of behaviors associated with anxiety, agitation, and aggression. The administration of PRN medication rests solely on the nursing staff and their ability to use autonomous clinical decision-making to distinguish between different behaviors associated with those conditions prior to the administration of PRN medication. For the past 30 years, research has recognized the lack of national standards, assessment criteria, and ethical practices when administrating PRN medications in the acute inpatient setting. The purpose of this study was to identify nurses' knowledge of signs and symptoms of anxiety or agitation in the acute care setting. The model used to guide this research is the Synergy Model of Patient Care. The design for this research study was a descriptive design using a case study approach. This study was conducted at a nonprofit, general medical-surgical community hospital in Rhode Island specializing in rehabilitation and psychiatric services. The target sample consisted of all registered nurses working on three study units. Two case studies, each portraying a patient experiencing symptoms or behaviors of anxiety and agitation were used to measure nurses' knowledge of signs and symptoms of anxiety and agitation. A total of 17 RNs (N=17) participated in this research project. This research implied that there were gaps in clinical knowledge and variations in practice when nurses were asked to recognize symptoms of anxiety or behaviors associated with agitation.