This term is generally best to avoid. Many people with lived experiences of mental ill-health don’t apply this term to themselves, it’s important to check with people what terms they prefer.
The term “mental illness” can add to social stigma surrounding mental health, so it’s important to understand what it refers to, and to avoid using it where possible.
Mental illness refers specifically to a clinical diagnosis. These diagnoses usually describe various mental health symptoms which can interfere with an individual’s cognitive, emotional or social abilities. The “illness” diagnosis-based medical model of mental health is only one way of understanding mental health.
Individuals who receive a diagnosis may strongly identify with their diagnosis as a way to understand themselves and find support, or they might not, as the diagnosis might not appropriately describe their experience.
Many people who have received diagnoses prefer not to use the term “mental illness” as it reduces complex experiences to a medical diagnosis.
Mental illnesses are diverse, and each can occur with a varying degree of severity.
The preferred term is “person/people with a lived experience of mental illness/mental ill-health” though if referring to an individual, check how they would like to be referred to.
It’s important to use person-first language, that is “person with a lived experience of mental ill health” rather than “mentally ill person”.