Mental health is the well-being of the brain and mind. Since little is known about the actual workings of the physical brain, scientists make assessments of mental health by looking at external cues such as human behavior and intelligence tests.
In the Western conception, there are two basic senses of what a mentally healthy mind is:
First, there's the sense of a mind which is free from disease, which lacks mental illness, which functions, which is sufficient to permit a person to do daily tasks such as hold down a job or be in a relationship. In this sense, a person who is generally considered mentally healthy if he or she behaves normally in terms of accepted and standard behavioral and social norms. This sense perhaps characterizes a majority of people today. For further information, see Mental illness.
Second, there's the sense of a mind well-adapted to its environment, so it helps a person grow, plan, succeed in life with effective relationships to other people, enjoy life and beauty and art, and thrive as a fully functioning human. In this sense, a person is mentally healthy if he or she is enjoying life to a great extent. This designation perhaps characterizes few people today. For further information, see mentally healthy mind.