What characterizes depersonalization/derealization disorder?

Depersonalization/derealization disorder is characterized primarily by feelings of detachment from one's surroundings or self. Individuals experiencing this disorder often describe a sense of being outside of their own body or feeling disconnected from their environment, which can lead to a distorted perception of reality. This detachment can manifest as a feeling that the world around them is unreal or dreamlike (derealization), or a feeling of separation from oneself (depersonalization).

The other options, while they may describe different psychological phenomena or disorders, do not specifically define the key characteristics of depersonalization/derealization disorder. The sudden lack of personal identity is more closely associated with dissociative identity disorder. Loss of interest in life could indicate depression. Lastly, excessive worry about the future is more indicative of anxiety disorders. Therefore, the correct answer highlights the essential feature of feeling detached from one's surroundings, which is central to the understanding of depersonalization/derealization disorder.