Organic brain syndrome is a blanket term used to refer to cases in which people experience cognitive impairments as a result of physical damage to the brain. This term is widely regarded as obsolete and is primarily seen in old texts. However, there may be cases in which it is still used. One problem with this term is that it is not very precise, and thus provides very little meaningful information which could be used to develop a treatment plan.
The concept of organic brain syndrome arose in the field of psychiatry as people began to separate the causes of different types of conditions involving the brain. Psychological conditions in which no physical changes to the brain could be observed were known as functional disorders, while cases in which the brain was physically damaged were known as organic. Dividing conditions by cause was meant to assist with narrowing down the diagnosis and providing appropriate treatment; a psychologist cannot treat a stroke, for example, while a neurosurgeon may not be helpful with an anxiety disorder.
In the case of acute organic brain syndrome, the onset of the condition is sudden. Chronic organic brain syndrome involves persistent changes in cognitive function which are the result of damage to the brain. The changes observed in patients with physical changes to the brain can be both neurological and psychological in origin. For example, some people who experience traumatic brain injuries undergo personality changes in addition to experiencing neurological symptoms like difficulty walking or speaking.
Causes of organic brain syndrome can include trauma, disease, and exposure to neurotoxins. Trauma can cause a variety of types of damage to the brain on a cellular level and neurology researchers are constantly learning more about the long term damage which can be caused by trauma. For example, shearing forces in the brain can lead to a diffuse axonal injury in which neurons are damaged, but the damage does not show up on medical imaging studies because it happens on a level that is too small to detect.
Disease includes neurodegenerative diseases like Alzheimer's along with cardiovascular disease which impairs circulation to the brain, stroke, conditions which lead to low levels of oxygen in the brain, and so forth. Neurotoxins may be ingested accidentally, as for example in people injured in industrial accidents, or as a result of recreational drug and alcohol use.
If someone is said to have organic brain syndrome, additional testing and evaluation is needed to determine the cause so that an appropriate course of treatment can be developed. Treatment may be capable of arresting damage in addition to helping patients recover from damage.