In our daily practices of neuropsychiatry, our patients (when they are able), and especially their families, often communicate to us the following: "Life was hard enough before this condition descended upon us. Before the illness, like most people, we struggled to get by on a day-to-day basis: working hard at our occupations, managing our finances, caring for our family took just about everything we had to give. We never anticipated or were prepared for anything that would be so disruptive or devastating to our everyday lives." The very nature of most neuropsychiatric disorders is that there have been prolonged periods of time that preceded the neurological condition wherein the individual had experienced a satisfactory level of functioning in most of the important dimensions of his or her life. Most often the onset of neuropsychiatric conditions appears to patients and their families to be sudden, as manifested by stroke, traumatic brain injury, seizure disorders, and brain tumors. Because of these conditions' long-term implications, the diagnosis of even those neuropsychiatric disorders that have subtle, progressive onsets—such as Parkinson's disease, Alzheimer's disease, Huntington's disease, multiple sclerosis, and many others—is equally shocking and overwhelming to patients and their families alike. Very few other medical conditions are as disabling to so many vital dimensions of life as the neuropsychiatric conditions covered in this section, which so prominently affect attention, orientation, cognition, memory, mood, motivation, and control of impulse.