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Neurocognitive disorder

BrainBrain

Organic mental disorder (OMS); Organic brain syndrome

Definition

Neurocognitive disorder is a general term that describes decreased mental function due to a medical disease other than a psychiatric illness.

Neurocognitive disorders are grouped into three subcategories:

Delirium.
Mild neurocognitive disorder - some decreased mental function, but able to stay independent and do daily tasks.
Major neurocognitive disorder - decreased mental function and loss of ability to do daily tasks. Also called dementia.

Causes

Listed below are conditions associated with neurocognitive disorder.

BRAIN INJURY CAUSED BY TRAUMA

Bleeding into the brain (intracerebral hemorrhage)
Bleeding into the space around the brain (subarachnoid hemorrhage)
Blood clot inside the skull but outside the brain and its covering, which may cause pressure on the brain (subdural hematoma or epidural hematoma)
Concussion

BREATHING CONDITIONS

Low oxygen in the body (hypoxia)
High carbon dioxide level in the body (hypercapnia)

CARDIOVASCULAR DISORDERS

Dementia due to many strokes (multi-infarct dementia)
Heart infections (endocarditis, myocarditis)
Stroke
Transient ischemic attack (TIA)

DEGENERATIVE DISORDERS

Alzheimer disease (also called senile dementia, Alzheimer type)
Creutzfeldt-Jakob disease
Diffuse Lewy body disease
Huntington disease
Normal pressure hydrocephalus
Parkinson disease
Pick disease

AUTOIMMUNE DISEASES

Multiple sclerosis
Autoimmune encephalitis

DEMENTIA DUE TO METABOLIC CAUSES

Kidney disease
Liver disease
Thyroid disease (hyperthyroidism or hypothyroidism)
Vitamin deficiency (B1, B12, or folate)

DRUG AND ALCOHOL-RELATED CONDITIONS

Alcohol withdrawal state
Intoxication from drug or alcohol use
Medicine effect, such as corticosteroids, sedative-hypnotics, antihistamines, and antidepressants
Wernicke-Korsakoff syndrome, a long-term effect of deficiency of thiamine (vitamin B1)
Withdrawal from medicines, such as sedative-hypnotics and corticosteroids

INFECTIONS

Any sudden onset (acute) or long-term (chronic) infection
Blood poisoning (septicemia)
Brain infection (encephalitis)
Meningitis (infection of the lining of the brain and spinal cord)
Prion infections, such as mad cow disease
Late-stage syphilis

Complications of cancer and cancer treatment with chemotherapy and radiation therapy to the brain can also lead to neurocognitive disorder.

Other conditions that may mimic neurocognitive disorder include:

Symptoms

Symptoms can differ based on the disease. In general, neurocognitive disorder causes:

Agitation
Confusion
Long-term loss of brain function (mild cognitive impairment or dementia)
Severe, short-term loss of brain function (delirium)

Exams and Tests

Tests depend on the disorder, but may include:

Blood tests
Neuropsychological testing
Electroencephalogram (EEG)
Head CT scan
Head MRI
Lumbar puncture (spinal tap)

Treatment

Treatment depends on the underlying condition. Many conditions are treated mainly with rehabilitation and supportive care to help the person with activities lost due to areas where brain function is affected.

Medicines may be needed to reduce aggressive behaviors that can occur with some of the conditions.

Outlook (Prognosis)

Some disorders are short-term and reversible. But many are long-term or get worse over time.

Possible Complications

People with neurocognitive disorder often lose the ability to interact with others or function on their own.

When to Contact a Medical Professional

Contact your health care provider if:

You have been diagnosed with neurocognitive disorder and you are uncertain about the exact disorder.
You have symptoms of this condition.
You have been diagnosed with neurocognitive disorder and your symptoms become worse.

References

Beck BJ, Smith FA, Stern TA. Mental disorders due to another medical condition. In: Stern TA, Wilens TE, Fava M, eds. Massachusetts General Hospital Comprehensive Clinical Psychiatry. 3rd ed. Philadelphia, PA: Elsevier; 2025:chap 21.

Inouye SK. Delirium and changes in mental status. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 361.

Knopman DS. Cognitive impairment and dementia. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 371.

Merrick ST, Glesby MJ. Systemic manifestations of HIV/AIDS. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 359.

Sorg EM, Jankauskaite G, Jacobs J. Psychiatric co-morbidities and complications of cancer and cancer treatment. In: Stern TA, Wilens TE, Fava M, eds. Massachusetts General Hospital Comprehensive Clinical Psychiatry. 3rd ed. Philadelphia, PA: Elsevier; 2025:chap 46.

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Review Date: 3/31/2024

Reviewed By: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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