Dementia is a progressive decline in thinking, memory, and the
ability to learn. People with dementia may need help with basic
activities, such as cooking and bathing. Some people with
dementia have problems with behavior. These problems may include
agitation, aggressive or paranoid behavior, sudden mood changes,
fits of anger and yelling, wandering, and inappropriate sexual
behavior. Some people may also feel out of touch with reality,
and they may have delusions or hallucinations.