The key feature of serious mental illness is that it results in serious functional impairment, which substantially interferes with one or more major life activities.

• A. True
• B. False
• C. It refers to the diagnosis label only
• D. It relates to risk of self-harm only

Answer: (A)

Serious mental illness is defined by substantial impairment in functioning, not just the presence of a diagnosis. When a mental health condition significantly interferes with major life activities—such as work or school, relationships, and daily self-care—it meets the threshold for seriousness. This emphasis on functional impact helps distinguish choosing to seek treatment from the mere existence of symptoms. The statement is true because the defining feature is the degree to which functioning is disrupted, not simply having a diagnosis label or concerns about self-harm.