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Neurocognitive Disorders (Mild and Major)

Reviewed by Psychology Today Staff

Neurocognitive disorders, mild and major, include a group of conditions which were once all grouped under the umbrella term “dementia.” The conditions involve similar cognitive impairments and decline, and most often affect the elderly. The primary symptoms across the conditions involve declines in cognitive performance in areas including attention, executive function, learning and memory, language, motor skills, or social cognition. Since cognition is so critical to daily human functioning, these disorders can be extremely debilitating and lead to severe reductions in individuals’ quality of life.

The primary recognized neurocognitive disorders include:

  • Alzheimer’s disease
  • frontotemporal degeneration
  • Huntington’s disease
  • Lewy body disease
  • traumatic brain injury (TBI)
  • Parkinson’s disease
  • prion disease, such as Creutzfeldt-Jakob disease or Bovine Spongiform Encephalopathy (“mad cow disease”)
  • dementia/neurocognitive issues due to HIV infection
  • vascular dementia

Most of these conditions are more prevalent in people over 65, and gradually progress over many years, but early onset is not rare, and some, such as HIV, will affect younger as well as older people, while others, specifically traumatic brain injury, can affect anyone, including children. When symptoms emerge among younger people, they are relatively easy to detect and diagnose; when they emerge very late in life, they may go unnoticed.

Alzheimer's disease accounts for the majority of cases of neurocognitive disorders (NCDs); it affects more than 5 million Americans. It, along with several of the other recognized disorders, affects memory, thinking, and reasoning; some, like Parkinson’s disease and Lewy body disease, also affect the motor system.

These disorders can be categorized and diagnosed as either major or mild (also known as slight cognitive impairment), depending on the severity of the symptoms; generally, a neurocognitive disorder is considered mild if it does not affect a person’s ability to live independently.

Major cognitive disorder is estimated to affect 1 to 2 percent of people by age 65 and as much as 30 percent of the population by age 85; the prevalence of minor cognitive disorders is harder to estimate, but they are believed to affect between 2 and 10 percent of 65-year-olds, and as many as 25 percent of 85-year-olds.

For more, see Dementia.


Whether diagnosed as mild or major, the mental and behavioral symptoms of the nine recognized neurocognitive disorders are similar, according to the DSM-5, and typically include a decline in thinking skills presenting as:

  • difficulty with planning
  • an inability to make decisions
  • trouble focusing on tasks
  • an inability to remember the names of objects and people
  • struggles with performing daily tasks
  • speaking or behaving in ways that are not socially accepted

Neurocognitive disorders can also affect an individual’s ability to regulate their emotions, especially anger, and their personalities may change in other ways as well. The effects on a person’s ability to follow directions and execute complex activities often manifest as trouble with cooking, cleaning, or sticking to a medication regimen, as well as bathing, eating, dressing, and using the bathroom.

When there is only a slight decline in one or more of these functions, the disorder is considered mild. When the decline in one of more of these functions is severe, the disorder is considered major. Where an individual falls on the spectrum of neurocognitive impairment is typically determined by the degree to which the condition affects their level of independence.

A given person’s decline is typically gradual, but will vary from case to case. Typically, decline is slow during early stages of a neurocognitive disease; it may be years before a condition becomes truly debilitating. For people with both mild and major neurocognitive disorders, though, the decline is generally sufficiently noticeable to raise the concern of loved ones or health-care providers; after that, they can be confirmed through testing by a neuropsychologist, and a diagnosis can be made by a neurologist or geriatric psychiatrist.

For a diagnosis of neurocognitive disorder to be made, the symptoms must be associated with a medical condition, and not another mental health problem, such as delirium, major depressive disorder, or schizophrenia.

How can you tell the difference between normal memory decline and a neurocognitive disorder?

In the normal course of aging, people often experience some loss of memory, but an NCD causes notable change outside of any normal expected progression. These problems typically become concerning at the point when they are disabling or when they prevent normal, everyday functioning. Some key warning signs include trouble using words in speaking and writing, difficulty working with numbers and making plans, struggling to complete routine tasks, difficulty finding a familiar place, losing track of the normal passage of time, and getting easily confused.

Do neurocognitive disorders affect more men or women?

The primary risk factor for major and mild neurocognitive disorders is age; the older the person, the greater the risk. Women are more likely than men to be diagnosed with NCDs, but that is almost entirely attributable to the fact that women tend to live longer.

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Neurocognitive disorders are not developmental; they are acquired conditions representing underlying brain pathology resulting in a decline in cognitive faculties. They are caused by brain damage in areas that affect learning and memory, planning and decision making, the ability to correctly use and understand language, hand-eye coordination, and/or the ability to act within social norms, such as dressing appropriately for the weather or occasion, showing empathy, and performing routine tasks.

Can a neurocognitive disorder be caused by substance abuse?

Yes. Substance/medication-induced major or mild neurocognitive disorder is a condition brought on by excessive alcohol or drug use, leading to persistent, enduring cognitive impairment distinct from typical intoxication. When the condition is caused by methamphetamine use, the symptoms are most likely to mimic vascular dementia, as the drug can cause vascular injury. The prevalence of substance/medication-induced NCD is not known but is more common in individuals whose persistent alcohol or drug use continues well past age 50, especially those whose onset of persistent use began in their teens or 20s.

How prevalent are neurocognitive disorders caused by HIV?

Major or mild neurocognitive disorder caused by HIV infection is more common in those for whom immune deficiency was a pre-existing condition, and/or those individuals with especially high viral loads in their cerebrospinal fluid. It is estimated that a third to a half of all HIV patients will experience symptoms of mild neurocognitive disorder, and that about 5 percent could be diagnosed with major NCD due to their infection.


There is no cure for most types of neurocognitive disorders, but certain treatments can help alleviate the symptoms temporarily. A doctor my prescribe antidepressants or medications that treat memory loss and other symptoms. For many patients with neurocognitive disorders, ongoing psychotherapy and psychosocial support is often necessary for clear understanding and proper management of the disorder, to establish an adequate caregiving regimen, and to maintain quality of life. Because of the level of support that is often necessary, spouse, partners, and family members often take part in these sessions.

What can someone do to prevent or slow the advance of neurocognitive disorders?

Healthy lifestyle choices can generally help reduce the risk of serious cognitive impairment. Specifically, research suggests that making certain lifestyle changes may help reduce a person’s risk of developing Alzheimer’s disease. These changes include engaging in regular physical activity (which increases blood and oxygen flow in the brain) and maintaining good hydration and adopting a heart-healthy diet based on fruits, vegetables, and whole grains and limiting intake of sugar and saturated fats. Staying socially engaged and maintaining a supportive network of friends and relatives can also help protect against NCDs, as can remaining cognitively engaged through reading, puzzles, and novel activities. Experts also strongly advise that people prioritize sufficient sleep, limitg alcohol consumption, and not smoke.

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Hugo J, Ganguli M. Dementia and Cognitive Impairment. Clinics in Geriatric Medicine. August 2014;30(3):421-442.
Understanding Mental Disorders. Dementia and Other Memory Problems. 2015; American Psychiatric Association.
Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition
Last updated: 04/04/2019