Organic Mental Disorder Causes and Treatment

A woman with dementia at a day facility for the elderly.
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An organic mental disorder is a previously used term to describe a dysfunction of the brain that was meant to exclude psychiatric disorders. It is currently known under the category of neurocognitive disorders. It describes reduced brain function due to illnesses that are not psychiatric in nature. 

Sometimes the term organic mental disorder is used interchangeably with the terms organic brain syndrome (OBS), chronic organic brain syndrome, or neurocognitive disorder—this latter term is the one used more commonly now.


Organic mental disorders are disturbances that may be caused by injury or disease affecting brain tissues as well as by chemical or hormonal abnormalities. Exposure to toxic materials, neurological impairment, or abnormal changes associated with aging can also cause these disorders. Alcohol, or metabolic disorders such as liver, kidney, or thyroid disease, or vitamin deficiencies, may be factors too.

Concussions, blood clots, or bleeding in or around the brain from trauma may lead to organic brain syndrome. Low oxygen in the blood, high amounts of carbon dioxide in the body, strokes, brain infections, and heart infections can lead to an organic mental disorder as well.

Degenerative disorders like Parkinson's disease, Alzheimer's disease, Huntington disease, and multiple sclerosis may also be contributing factors.


A person with an organic mental disorder may have difficulty concentrating for a long period of time. Others may get confused while performing tasks that seem routine to others. Managing relationships and collaborating and communicating with colleagues, friends, or family may also prove difficult.

Overall the severity of the symptoms and the type of symptoms a person has varies, depending on the cause of their disorder.

Primary Symptoms

  • Confusion
  • Agitation
  • Irritability
  • A change in behavior, impaired brain function, cognitive ability, or memory

If you or your loved one is experiencing any of these symptoms, it's important to seek medical care as soon as possible. A serious medical problem may have caused these symptoms to surface, and early intervention may be key.

Diagnosis and Treatment

Blood tests, spinal taps, or an electroencephalogram may be administered to diagnose organic brain syndrome or an organic mental disorder. Imaging of the brain, like a CT scan or MRI, is also useful, depending on a doctor's suspicion.

Treatments for organic mental disorders vary on what the underlying cause of the disorder is. Medication may be prescribed or rehabilitation therapy may help patients recover function in the parts of the brain affected by the organic mental disorder.


While some organic mental disorders may only be temporary, others often get worse with time. Disorders that don't respond to treatment may lead the patient to lose the ability to function independently or to interact with others.

In short, the chance of recovery or the outlook of a person's disorder depends on a number of factors, mostly what the cause is behind the impaired brain function. While the diagnosis of an organic mental disorder (or neurocognitive disorder, as it is now referred to) can be frightening, you are not alone, and there are ample resources available to help you or your loved one.

7 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Ann Logsdon
Ann Logsdon is a school psychologist specializing in helping parents and teachers support students with a range of educational and developmental disabilities.