A nurse is assisting with the admission of a client to an acute mental health unit following a suicide attempt. The client has a history of depression, substance abuse, and anorexia nervosa. Which of the following actions should the nurse take first?

This option is not the first priority because while addressing anorexia nervosa is important, safety concerns related to the suicide attempt and potential substance abuse take precedence. Making a weight gain contract requires the client's cooperation and readiness, which may not be feasible immediately upon admission. This is the most appropriate initial action. One-to-one observation ensures constant monitoring of the client's safety and prevents further harm, such as another suicide attempt or self-harm. Given the client's history of depression and recent suicide attempt, ensuring their safety is paramount. While assessing the severity of depression is crucial, it is secondary to ensuring immediate safety in this context. The client's safety must be established first through continuous observation and intervention. While important to understand the substances involved in the suicide attempt, this action is secondary to ensuring ongoing safety through direct observation. Toxicology results can guide subsequent treatment decisions but are not as urgent as immediate safety measures.