What is a Geriatrician? A Geriatrician is a physician who has been specifically trained to deal with the medical issues of older adults. They understand the different needs of the older population as concerns medications, changing physical conditions and mental changes. They can diagnose dementia. Many older adults should seek a geriatrician when they reach 65 or older. If the older person is attached to their doctor, check to see if the doctor has been trained in geriatrics. If not, they may not understand that older adults cannot handle the same dosage of medication that a 30 year old can handle.