What aspect of functioning is typically affected by depression?

Depression primarily impacts mood and behavior, which makes this choice the correct answer. When a person experiences depression, it often manifests through persistent feelings of sadness, hopelessness, and a lack of interest or pleasure in activities they once enjoyed. These emotional changes can lead to altered behaviors, such as withdrawal from social interactions, decreased motivation, and reduced engagement in daily tasks.

While other aspects, such as physical appearance or social skills, can be indirectly affected as a result of these mood changes, it is the mood and behavior that are most directly and profoundly influenced by depression. Cognitive abilities, while sometimes affected in terms of concentration or decision-making, are not as central to the primary symptoms of depression as mood and behavior.