Which of the following is a major risk factor for undiagnosed depression?

Impairment in daily function is a major risk factor for undiagnosed depression because it often indicates that an individual is struggling to cope with daily tasks, which can be a consequence of underlying depressive symptoms. When a person's ability to perform routine activities—such as work, school, or personal care—is impacted, it may reflect the presence of mental health issues like depression that have not been recognized or properly diagnosed.

In contrast, high academic performance generally indicates a capability to manage responsibilities effectively, which would be less likely associated with undiagnosed depression. Increased social interactions may suggest strong support systems and engagement with others, which can actually serve as protective factors against mental health issues. Similarly, a lack of physical illnesses would usually be seen as a positive indicator of health, not one that contributes to the risk of undiagnosed depression. Overall, impairment in daily function serves as a critical warning sign that mental health issues, including depression, may be present and in need of assessment.