It is common for persons with dementia to be anxious or agitated. It does occur as the disease advances. Agitation covers a range of behaviors, like irritability, sleeplessness, and verbal or physical aggression. Such behaviors may be due to varied factors. Medical condition, medication, fatigue, fear, and some environmental circumstances can trigger or worsen their ability to think. Also, the person also experiences a profound loss of his ability to process stimulus and new information. He feels that his sense of control is being taken away from him.