What is one key symptom of anxiety in a patient?

Excessive worry is a key symptom of anxiety in a patient because it encapsulates the overwhelming feelings of apprehension or fear that individuals with anxiety disorders often experience. This symptom can manifest in various forms, leading to an inability to control one's thoughts or anxieties about different aspects of life, such as personal health, work, or social interactions. In anxiety disorders, this worry is disproportionate to the situation, can be difficult to manage, and often affects the individual's daily functioning and quality of life.

While other options like lack of motivation, persistent sadness, and reduced appetite may arise in different psychological conditions, they are not as specifically indicative of anxiety. For example, lack of motivation can be more closely associated with depression, while persistent sadness is a hallmark of depressive disorders, and reduced appetite can occur in various mental health issues but is not specifically related to anxiety. Thus, excessive worry stands out as a primary and defining symptom of anxiety.