Mental health is a measurement of a person’s psychological, social and emotional well-being. It affects the way people think, feel and act. Poor mental health may lead to mental illnesses such as anxiety and depression, but it may also affect physical health. People of every age can improve or maintain good mental health. Maintaining good mental health isn’t just important for your mood or emotional well-being. Researchers have established a connection between taking care of the mind and helping the body.