Dementia, mental decline, or dementia is a disorder that manifests as a group of related symptoms, which usually appear when the brain is damaged by injury or disease. Symptoms include progressive impairments in memory, thinking, and behavior, which negatively impact a person's ability to function and perform daily activities. Aside from memory impairment and disturbances in thinking patterns, the most common symptoms include emotional problems, difficulties with language, and decreased motivation. Symptoms can be described as occurring on a continuum over several stages. Consciousness is not affected. Dementia ultimately has a significant impact on the individual, caregivers, and social relationships in general. A diagnosis of dementia requires noting a change from a person's usual mental functioning, and a cognitive decline greater than that caused by normal aging. Many diseases and injuries to the brain, such as stroke, can lead to dementia. However, the most common cause is Alzheimer's disease, a neurodegenerative disorder. The International Classification of Diseases classifies dementia as a neurocognitive disorder with several forms or subcategories. Dementia is listed as an acquired brain syndrome, characterized by a decline in cognitive function, and contrasted with neurodevelopmental disorders. Dementia subtypes may be based on a known disorder, such as Parkinson's disease; Huntington's disease; vascular disease, vascular dementia—vascular brain injury, including stroke, often leads to vascular dementia; Lewy body disease; frontotemporal lobar degeneration; or a number of other medical conditions, including HIV infection, which causes HIV-related dementia; and prion diseases. Easily reversible dementias include hypothyroidism, vitamin B12 deficiency, and Lyme disease. Diagnosis is usually based on history and cognitive testing using imaging. Blood tests may be done to rule out other possible reversible causes, such as an underactive thyroid or vitamin B12 deficiency, and to determine the subtype. One commonly used cognitive test is the Mini Medical Status Examination. The biggest risk factor for developing dementia is old age, but dementia is not a normal part of aging. Dementia has two main forms, considering its causes, which are: Alzheimer's disease can be diagnosed based on the following symptoms according to the criteria of the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders issued by the American Psychiatric Association (DSM-4), which are summarized as follows: A. A continuous decline in cognitive abilities represented by each of the following: B. The cognitive impairment mentioned in both A and 2) leads to a clear impairment in social or professional functions, and represents a clear decline compared to the level at which these functions were before that. C. The course of the condition is characterized by a gradual appearance of symptoms and a continuous deterioration in cognitive abilities. D. The cause of the cognitive impairment mentioned in both A and 2) must not be any of the following: E. This deterioration in cognitive abilities does not occur only during cases of delirium. F. This deterioration in cognitive abilities cannot be explained by cases of another mental disorder such as: depression or schizophrenia. Dementia resulting from multiple cerebral infarction can be diagnosed based on the following symptoms according to the criteria of the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders issued by the American Psychiatric Association (DSM-4), which are summarized as follows: A. A continuous decline in cognitive abilities represented by each of the following: B. The cognitive impairment mentioned in both A and 2) leads to a clear impairment in social or professional functions, and represents a clear decline compared to the level of these functions before that. C. Specific neurological symptoms and signs known to doctors indicate damage or dysfunction in specific areas of the brain, and the doctor sees that they are related to the deterioration of cognitive abilities. D. This deterioration in cognitive abilities does not only occur during cases of delirium. Dementia has multiple causes, which we summarize as follows: Dementia occurs in different forms depending on its cause. However, the final result, regardless of the cause, is often damage to brain cells. Successive studies have found that there is a severe deficiency in the nerve fluid called acetylcholine, in addition to the appearance of changes in brain cells indicating their fibrosis and damage. The risk of developing dementia generally increases with age, especially after the age of 65. The incidence of dementia is estimated at about 2% between the ages of 65-69, increasing to 5% between 75-79, then reaching 20% between the ages of 85-89, and 50% among those over the age of 90. Alzheimer's disease is the most common form of dementia, and occurs in women three times more often than in men. Multiple infarct dementia occurs more often in men because men are more likely to suffer from causes of infarctions such as atherosclerosis and high blood pressure. The prevalence of this type of dementia varies from one society to another due to prevailing dietary patterns, unlike Alzheimer's, which is equally prevalent in several societies around the world. The World Health Organization estimates that there are about 10 million new cases of dementia annually. There are a number of organic and psychological diseases that resemble dementia. Some organic diseases were previously mentioned when discussing the causes. Other conditions that resemble dementia are: Treatment of dementia varies according to its causes. There are some cases of dementia that are curable, such as cases resulting from vitamin deficiency, malnutrition, hypothyroidism, etc., because these causes can be treated, and then mental abilities can return to normal as they were. As for the drugs used in cases of dementia, they are as follows: Cases of dementia that cannot be treated are considered chronic cases. If left untreated, the patient's mental abilities continue to deteriorate until he loses the ability to take care of his simplest affairs, such as eating and drinking... He may also lose the ability to control his exits, and may go out at inappropriate times and be exposed to harm or loss, especially when the patient's physical condition helps him move and walk, which requires constant monitoring and closing the doors. These cases require a great effort from his family, which may be at the expense of their work and other aspects of their lives. In most cases, dementia cases that have no known treatable cause cannot be cured. Therefore, the course of these cases is characterized by slow or rapid deterioration until death, within a period ranging from 5-10 years. However, the drugs used to treat Alzheimer's disease may contribute to reducing the acceleration of deterioration in mental ability or may lead to stopping it for a period that may be long or short, depending on various personal and therapeutic factors estimated by the treating physician.