Geriatric psychology is a subfield of psychology that specializes in the mental and physical health of individuals in the later stages of life. These specialized psychologists study a variety of psychological abilities that deplete as aging occurs such as memory, learning capabilities, and coordination. Geriatric psychologists work with elderly clients to conduct the diagnosis, study, and treatment of certain mental illnesses in a variety of workplace settings. Common areas of practice include loneliness in old age, depression, dementia, Alzheimer's disease, vascular dementia, and Parkinson's disease.