Alzheimer Disease is the most common cause of dementia (loss of memory), which is an acquired (not present since birth) intellectual and behavioral impairment of sever intensity to significantly interfere with social and occupational functioning of an individual. The cause of Alzheimer disease is unknown. The existing research on the illness suggests that most cases of Alzheimer disease are caused by converging risk factors that include advancing age, head injury, and lipoprotein E-epsilon 4 genotype among other risk factors that appear to trigger the illness. Treatment of Alzheimer disease is based on developing theories of its cause and on the need to alleviate its cognitive (intellectual) and behavioral manifestations. To date, no interventions have been shown to convincingly prevent Alzheimer disease or slow its progression. Medical treatments for Alzheimer disease include psychotropic medications and behavioral interventions, cholinesterase inhibitors (ChEIs) and the avoidance of centrally acting anticholinergic medications, N-methyl-D-aspartate (NMDA) antagonists, and other and new therapeutic interventions.