Organic brain mental disorders are mental disorders caused by morphological alterations in the brain tissue and are thus distinguished from so-called functional mental disorders. The latter mainly refers to morphological alterations that have not yet been detected, limited to the current state of science. However, this distinction is relative. Organic brain mental disorders mainly refer to a group of mental disorders caused by organic factors such as brain degenerative diseases, cerebrovascular diseases, intracranial infections, craniocerebral trauma, intracranial tumors or epilepsy that directly damage the brain. It does not include mental disorders caused by systemic infections, poisoning, somatic disorders and psychoactive substances. The common organic brain mental disorders are Alzheimer’s disease and other degenerative diseases, cerebrovascular disease, epileptic mental disorders, intracranial infections, and other major types of mental disorders. Common organic brain syndromes Organic brain syndromes are usually divided into two categories, acute and chronic, according to their course and clinical manifestations. They can exist in a disease process alone or co-exist under certain conditions. Acute organic brain syndromes Acute organic brain syndromes are caused by diffuse, temporary lesions in the brain, mainly related to widespread metabolic disorders in the brain. The clinical features are acute or subacute onset, with decreased clarity of consciousness as the main clinical manifestation, accompanied by inattention, cognitive impairment and anxiety and depression, and some patients may have involuntary movements. If symptoms such as hallucinations, delusions, confusion, or incoherent thinking are also more prominent, it is called delirium. It is common in acute cerebral organic mental disorder, and also seen when chronic cerebral organic mental disorder is suddenly aggravated. Clinical treatment is based on the control of the primary disease, and when there are obvious psychotic symptoms, antipsychotic drugs can be applied in small doses. The syndrome is short-lived, mostly resolving within a few hours or days, and can be transformed into a chronic organic brain syndrome in individual cases. Chronic organic brain syndrome Chronic organic brain syndrome is mainly caused by chronic lesions in the brain, with a slow, insidious onset and a long course, and mostly irreversible damage. The common clinical symptoms include dementia syndrome, amnesia syndrome and personality change, etc. 1, dementia syndrome Most of the widespread damage to the brain caused by the clinical manifestations of progressive intelligence loss, mostly accompanied by personality changes and memory loss. It is seen in brain degenerative diseases and chronic cerebrovascular lesions, and a few can be caused by poisoning, trauma, tumor, infection and metabolism. There is no special treatment method. Amnesia syndrome is a selective or focal cognitive dysfunction caused by organic brain lesions, mainly characterized by near-event amnesia. The clinical manifestation is that the patient forgets the recent events, especially the names of people, places and numbers, instantly. In order to fill this memory gap, fictitious or misrepresentation is often produced. The patient is conscious at this time and has relatively intact cognitive function, which may be accompanied by slowness and lack of initiative. When loss of near-matter memory, disorientation, and fictitiousness coexist, it is called Korsakoff syndrome. It is mainly seen as a result of alcoholism-induced mental disorder, which is the result of alcoholism secondary to B-vitamin deficiency, thus causing damage to mesencephalic and frontal lobe structures such as the papillae, hippocampus, and mediodorsal nucleus of the optic thalamus. The treatment is mainly B vitamin supplementation and symptomatic treatment. 3.Personality change Personality change is also a common symptom group of organic brain disorder. Patients may show impoliteness, inattention to personal hygiene, lack of responsibility and sympathy before there is no obvious memory and intelligence defects. This is followed by antisocial or indulgent sexual behavior. Some patients do not exhibit prominent behavioral manifestations, but have more pronounced emotional disorders, such as irritability, strong crying and laughing at every turn. Some patients may be stubborn and self-centered, or sensitive and suspicious, anxious and restless. It is common in traumatic brain injury, brain tumor, epilepsy, cerebral vascular sclerosis and brain degenerative disease. Clinical treatment remains focused on treating the primary cause.