A continuum of psychological and emotional well-being along which an individual moves periodically without having a mental illness. The World Health Organization defines mental health as a state of well-being in which an individual realizes their own potential, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to their community.

Psychiatric disorder or mental-health impairment, diagnosed by a specialist practitioner, that requires treatment, often including medication. Refer to Diagnostic and Statistical Manual of Mental Disorders (5th edition, DSM-5).