DSM-III

In DSM-III, this disorder is called Dementia

Diagnostic Criteria

A. A loss of intellectual abilities of sufficient severity to interfere with social or occupational functioning.

B. Memory impairment.

C. At least one of the following:

  1. impairment of abstract thinking, as manifested by concrete interpretation of proverbs, inability to find similarities and differences between related words, difficulty in defining words and concepts, and other similar tasks
  2. impaired judgment
  3. other disturbances of higher cortical function, such as aphasia (disorder of language due to brain dysfunction), apraxia (inability to carry out motor activities despite intact comprehension and motor function), agnosia (failure to recognize or identify objects despite intact sensory function), "constructional difficulty" (e.g., inability to cope three-dimensional figures, assemble blocks, or arrange sticks in specific designs)
  4. personality change, i.e., alteration or accentuation of premorbid traits

D. State of consciousness not clouded (i.e., does not meet the criteria for Delirium or Intoxication, although these may be superimposed).

E. Either (1) or (2):

  1. evidence from the history, physical examination, or laboratory tests, of a specific organic factor that is judged to be etiologically related to the disturbance
  2. in the absence of such evidence, an organic factor necessary for the development of the syndrome can be presumed if conditions other than Organic Mental Disorders have been reasonably excluded and if the behavioral change represents cognitive impairment in a variety of areas

Differential Diagnosis

Normal aging

The normal process of aging has been associated in a number of studies with a variety of different changes in intellectual function. The nature of these changes and whether they should be considered true decrements of function, however, remain controversial. The diagnosis of Dementia is warranted only if intellectual deterioration is of sufficient severity to interfere with social or occupational functioning. Dementia is not synonymous with aging.

Delirium

In Delirium there is also impairment of intellectual abilities, but it occurs in the context of clouding of consciousness; in Dementia the state of consciousness is normal. The clinical course of these two syndromes also differs. In Delirium symptoms typically fluctuate, whereas in Dementia they are relatively stable. An Organic Mental Disorder persisting in unchanged form for more than a few months suggests Dementia rather than Delirium.

Schizophrenia

Schizophrenia, especially when chronic, may be associated with some degree of intellectual deterioration. The absence of identifiable brain pathology helps rule out the additional diagnosis of Dementia.

Major depressive episode

Individuals with a major depressive episode may complain of memory impairment, difficulty in thinking and concentrating, and an overall reduction in intellectual abilities. They may also perform poorly on mental-status examination and neuropsychological testing. These features may suggest the possible diagnosis of Dementia, and this phenomenon is sometimes known as "pseudodementia." Depression, however, is primarily a disturbance of mood. Any cognitive deficits observed may be viewed as secondary to the disturbed affect. If sufficiently motivated to perform, individuals with depression usually demonstrate intact cognitive function. Dementia, on the other hand, is basically a disorder of intellectual function. Abnormalities of mood are less frequent and, when present, less pervasive than in depression. The clinical history also helps to differentiate between the two. In depressive pseudodementia, the onset can frequently be dated with some precision, and symptoms progress more rapidly than in true Dementia. In addition, there may be a history of previous mental illness. On formal mental-status testing there may be considerable variability in performance as opposed to the more consistently poor performance of individuals with Dementia. In the absence of evidence of a specific organic etiologic factor, if the features suggesting major depressive episode are at least as prominent as those suggesting Dementia, it is best to diagnose major depressive episode and to assume that the features suggesting Dementia are secondary to the depression. A therapeutic trial with an antidepressant drug or electroconvulsive therapy (ECT) (if not contraindicated) may clarify the diagnoses in that if the disorder is actually a major depressive episode, cognitive impairment may resolve as the mood improves.

Factitious Disorder

Factitious Disorder with Psychological Symptoms may mimic Dementia, but rarely.

DSM-IV

Disorders

  1. Dementia of the Alzheimer's Type
  2. Vascular Dementia
  3. Dementia Due to Other General Medical Conditions
    1. Dementia Due to HIV Disease
    2. Dementia Due to Head Trauma
    3. Dementia Due to Parkinson's Disease
    4. Dementia Due to Huntington's Disease
    5. Dementia Due to Pick's Disease
    6. Dementia Due to Creutzfeldt-Jakob Disease
  4. Substance-Induced Persisting Dementia
  5. Dementia Due to Multiple Etiologies
  6. Dementia NOS

Differential Diagnosis

Delirium

Memory impairment occurs in both delirium and dementia. Delirium is also characterized by a reduced ability to maintain and shift attention appropriately. The clinical course can help to differentiate between delirium and dementia. Typically, symptoms in delirium fluctuate and symptoms in dementia are relatively stable. Multiple cognitive impairments that persist in an unchanged form for more than a few months suggest dementia rather than delirium. Delirium may be superimposed on a dementia, in which case both disorders are diagnosed. In situations in which it is unclear whether the cognitive deficits are due to a delirium or a dementia, it may be useful to make a provisional diagnosis of delirium and observe the person carefully while continuing efforts to identify the nature of the disturbance.

Amnestic Disorders

An amnestic disorder is characterized by severe memory impairment without other significant impairments of cognitive functioning (i.e., aphasia, apraxia, agnosia, or disturbances in executive functioning).

Other Dementias

The presumed etiology determines the specific dementia diagnosis. If the clinician has determined that the dementia is due to multiple etiologies, multiple recordings based on the specific dementias and their etiologies should be used (see Dementia Due to Multiple Etiologies). In Vascular Dementia, focal neurological signs (e.g., exaggeration of deep tendon reflexes, extensor plantar response) and laboratory evidence of vascular disease judged to be related to the dementia are present. The clinical course of Vascular Dementia is variable and typically progresses in stepwise fashion. The presence of Dementia Due to Other General Medical Condition (e.g., Pick's disease, HIV) requires evidence from the history, physical examination, and appropriate laboratory tests that a general medical condition is etiologically related to the dementia. The onset of the deterioration (gradual or sudden) and its course (acute, subacute, or chronic) may be useful in suggesting the etiology. For example, the severity of the impairment in cognitive functioning often remains static after head injury, encephalitis, or stroke.

Multiple cognitive deficits that occur only in the context of substance use are diagnosed as Substance Intoxication or Substance Withdrawal. If the dementia results from the persisting effects of a substance (i.e., a drug of abuse, a medication, or toxin exposure), then Substance-Induced Persisting Dementia is diagnosed. Other causes of dementia (e.g., Dementia Due to a General Medical Condition) should always be considered, even in a person with Substance Dependence. For example, head injury is not infrequent during substance use and may underlie the dementia. Dementia of the Alzheimer's Type is currently a diagnosis of exclusion, and other causes for the cognitive deficits must first be ruled out. In addition, the course is characterized by gradual onset and continuing cognitive decline. In those cases in which there is insufficient evidence to determine whether the dementia is due to a general medical condition or is substance induced, Dementia Not Otherwise Specified should be recorded. Individuals may present with some but not all of the symptoms of dementia. Such presentations should be recorded as Cognitive Disorder Not Otherwise Specified.

Mental Retardation

Mental Retardation is characterized by significantly subaverage current general intellectual functioning, with concurrent impairments in adaptive functioning and with an onset before age 18 years. Mental Retardation is not necessarily associated with memory impairment. In contrast, the age at onset of dementia is usually late in life. If the onset of the dementia is before age 18 years, both dementia and Mental Retardation may be diagnosed if the criteria for both disorders are met. Documenting a significant deterioration in memory and in other cognitive skills, which is necessary for the diagnosis of dementia, may be difficult in persons under age 4 years. In individuals under age 18 years, the diagnosis of dementia should be made only if the condition is not characterized satisfactorily by the diagnosis of Mental Retardation alone.

Schizophrenia

Schizophrenia can also be associated with multiple cognitive impairments and a decline in functioning, but Schizophrenia is unlike dementia in its generally earlier age at onset, its characteristic symptom pattern, and the absence of a specific etiological general medical condition or substance. Typically, the cognitive impairment associated with Schizophrenia is less severe than that seen in Dementia.

Major Depressive Disorder

Major Depressive Disorder may be associated with complaints of memory impairment, difficulty thinking and concentrating, and an overall reduction in intellectual abilities. Individuals sometimes perform poorly on mental status examinations and neuropsychological testing. Particularly in elderly persons, it is often difficult to determine whether cognitive symptoms are better accounted for by a dementia or by a Major Depressive Episode. This differential diagnosis may be informed by a thorough medical evaluation and an evaluation of the onset of the disturbance, the temporal sequencing of depressive and cognitive symptoms, the course of illness, family history, and treatment response. The premorbid state of the individual may help to differentiate "pseudodementia" (i.e., cognitive impairments due to the Major Depressive Episode) from dementia. In dementia, there is usually a premorbid history of declining cognitive function, whereas the individual with a Major Depressive Episode is much more likely to have a relatively normal premorbid state and abrupt cognitive decline associated with the depression. If the clinician determines that both a dementia and Major Depressive Disorder are present with independent etiologies, both should be diagnosed.

Malingering and Factitious Disorder

Dementia myst be distinguished from Malingering and Factitious Disorder. The patterns of cognitive deficits presented in Malingering and Factitious Disorder are usually not consistent over time and are not characteristic of those typically seen in dementia. For example, individuals with Factitious Disorder or Malingering manifesting as dementia may perform calculations while keeping score during a card game, but then claim to be unable to perform similar calculations during a mental status examination.

Aging

Dementia must be distinguished from the normal decline in cognitive functioning that occurs with aging (as in Age-Related Cognitive Decline). The diagnosis of dementia is warranted only if there is demonstrable evidence of greater memory and other cognitive impairment than would be expected due to normal aging processes and the symptoms cause impairment in social or occupational functioning.

DSM-5

Disorders

  1. Major or Mild Neurocognitive Disorder Due to Alzheimer's Disease
  2. Major or Mild Frontotemporal Neurocognitive Disorder
  3. Major or Mild Neurocognitive Disorder With Lewy Bodies
  4. Major or Mild Vascular Neurocognitive Disorder
  5. Major or Mild Neurocognitive Disorder Due to Traumatic Brain Injury
  6. Substance/Medication-Induced Major or Mild Neurocognitive Disorder
  7. Major or Mild Neurocognitive Disorder Due to HIV Infection
  8. Major or Mild Neurocognitive Disorder Due to Prion Disease
  9. Major or Mild Neurocognitive Disorder Due to Parkinson's Disease
  10. Major or Mild Neurocognitive Disorder Due to Huntington's Disease
  11. Major or Mild Neurocognitive Disorder Due to Another Medical Condition
  12. Major or Mild Neurocognitive Disorder Due to Multiple Etiologies

Diagnostic Criteria

Major Neurocognitive Disorder

A. Evidence of significant cognitive decline from a previous level of performance in one or more cognitive domains (complex attention, executive function, learning and memory, language, perceptual-motor, or social cognition) based on:

  1. Concern of the individual, a knowledgeable informant, or the clinician that there has been a significant decline in cognitive function; and
  2. A substantial impairment in cognitive performance, preferably documented by standardized neuropsychological testing or, in its absence, another quantified clinical assessment.

B. The cognitive deficits interfere with independence in everyday activities (i.e., at a minimum, requiring assistance with complex instrumental activities of daily living such as paying bills or managing medications).

C. The cognitive deficits do not occur exclusively in the context of a delirium.

D. The cognitive deficits are not better explained by another mental disorder (e.g., major depressive disorder, schizophrenia).

Specify whether due to:

  • Alzheimer's disease
  • Frontotemporal lobar degeneration
  • Lewy body disease
  • Vascular disease
  • Traumatic brain injury
  • Substance/medication use
  • HIV infection
  • Prion disease
  • Parkinson's disease
  • Huntington's disease
  • Another medical condition
  • Multiple etiologies
  • Unspecified

Note: In some cases, there is a need for an additional recording for the etiological medical condition, which myst immediately precede the diagnostic recording for major neurocognitive disorder.

Specify:

  • Without behavioral disturbance: If the cognitive disturbance is not accompanied by any clinically significant behavioral disturbance.
  • With behavioral disturbance (specify disturbance): If the cognitive disturbance is accompanied by a clinically significant behavioral disturbance (e.g., psychomotor symptoms, mood disturbance, agitation, apathy, or other behavioral symptoms.

Specify current severity:

  • Mild: Difficulties with instrumental activities of daily living (e.g., housework, managing money).
  • Moderate: Difficulties with basic activities of daily living (e.g., feeding, dressing).
  • Severe: Fully dependent.

Mild Neurocognitive Disorder

A. Evidence of modest cognitive decline from a previous level of performance in one or more cognitive domains (complex attention, executive function, learning and memory, language, perceptual-motor, or social cognition) based on:

  1. Concern of the individual, a knowledgeable informant, or the clinician that there has been a mild decline in cognitive function; and
  2. A modest impairment in cognitive performance, preferably documented by standardized neuropsychological testing or, in its absence, another quantified clinical assessment.

B. The cognitive deficits do not interfere with independence in everyday activities (i.e., complex instrumental activities of daily living such as paying bills or managing medications are preserved, but greater effort, compensatory strategies, or accommodation may be required).

C. The cognitive deficits do not occur exclusively in the context of a delirium.

D. The cognitive deficits are not better explained by another mental disorder (e.g., major depressive disorder, schizophrenia).

Specify whether due to:

  • Alzheimer's disease
  • Frontotemporal lobar degeneration
  • Lewy body disease
  • Vascular disease
  • Traumatic brain injury
  • Substance/medication use
  • HIV infection
  • Prion disease
  • Parkinson's disease
  • Huntington's disease
  • Another medical condition
  • Multiple etiologies
  • Unspecified

Specify:

  • Without behavioral disturbance: If the cognitive disturbance is not accompanied by any clinically significant behavioral disturbance.
  • With behavioral disturbance (specify disturbance): If the cognitive disturbance is accompanied by a clinically significant behavioral disturbance (e.g., psychomotor symptoms, mood disturbance, agitation, apathy, or other behavioral symptoms.

Subtypes

Major and mild neurocognitive disorders (NCDs) are primarily subtyped according to the known or presumed etiological/pathological entity or entities underlying the cognitive decline. These subtypes are distinguished on the basis of a combination of time course, characteristic domains affected, and associated symptoms. For certain etiological substypes, the diagnosis depends substantially on the presence of a potentially causative entity, such as Parkinson's or Huntington's disease, or a traumatic brain injury or stroke in the appropriate time period. For other etiological subtypes (generally the neurodegenerative diseases like Alzheimer's disease, frontotemporal lobar degeneration, and Lewy body disease), the diagnosis is based primarily on the cognitive, behavioral, and functional symptoms. Typically, the differentiation among these syndromes that lack an independently recognized etiological entity is clearer at the level of major NCD than at the level of mild NCD, but sometimes characteristic symptoms and associated features are present at the mild level as well.

NCDs are frequently managed by clinicians in multiple disciplines. For many subtypes, multidisciplinary international expert groups have developed specialized consensus criteria based on clinicopathological correlation with underlying brain pathology. The subtype criteria here have been harmonized with those expert criteria.

Specifiers

Evidence for distinct behavioral features in NCDs has been recognized, particularly in the areas of psychotic symptoms and depression. Psychotic features are common in many NCDs, particularly at the mild-to-moderate stage of major NCDs due to Alzheimer's disease, Lewy body disease, and frontotemporal lobar degeneration. Paranoia and other delusions are common features, and often a persecutory theme may be a prominent aspect of delusional ideation. In contrast to psychotic disorders with onset in earlier life (e.g., schizophrenia), disorganized speech and disorganized behavior are not characteristic of psychosis in NCDs. Hallucinations may occur in any modality, although visual hallucinations are more common in NCDs than in depressive, bipolar, or psychotic disorders.

Mood disturbances, including depression, anxiety, and elation, may occur. Depression is common early in the course (including at the mild NCD level) of NCD due to Alzheimer's disease and Parkinson's disease, while elation may occur more commonly in frontotemporal lobar degeneration. When a full affective syndrome meeting diagnostic criteria for a depressive or bipolar disorder is present, that diagnosis should be recorded as well. Mood symptoms are increasingly recognized to be a significant feature in the earliest stages of mild NCDs such that clinical recognition and intervention may be important.

Agitation is common in a wide variety of NCDs, particularly in major NCD of moderate to severe severity, and often occurs in the setting of confusion or frustration. It may arise as combative behaviors, particularly in the context of resisting caregiving duties such as bathing and dressing. Agitation is characterized as disruptive motor or vocal activity and tends to occur with advanced stages of cognitive impairment across all of the NCDs.

Individuals with NCD can present with a wide variety of behavioral symptoms that are the focus of treatment. Sleep disturbance is a common symptom that can create a need for clinical attention and may include symptoms of insomnia, hypersomnia, and circadian rhythm disturbances.

Apathy is common in mild and mild major NCD. It is observed particularly in NCD due to Alzheimer's disease and may be a prominent feature of NCD due to frontotemporal lobar degeneration. Apathy is typically characterized by diminished motivation and reduced goal-directed behavior accompanied by decreased emotional responsiveness. Symptoms of apathy may manifest early in the course of NCDs when a loss of motivation to pursue daily activities or hobbies may be observed.

Other important behavioral symptoms include wandering, disinhibition, hyperphagia, and hoarding. Some of these symptoms are characteristic of specific disorders, as discussed in the relevant sections. When more than one behavioral disturbance is observed, each type should be notes in writing with the specifier "with behavioral symptoms."

Differential Diagnosis

Normal cognition

The differential diagnosis between normal cognition and mild NCD, as between mild and major NCD, is challenging because the boundaries are inherently arbitrary. Careful history taking and objective assessment are critical to these distinctions. A longitudinal evaluation using quantified assessments may be key in detecting mild NCD.

Delirium

Both mild and major NCD may be difficult to distinguish from a persistent delirium, which can co-occur. Careful assessment of attention and arousal will help to make the distinction.

Major depressive disorder

The distinction between mild NCD and major depressive disorder, which may co-occur with NCD, can also be challenging. Specific patterns of cognitive deficits may be helpful. For example, consistent memory and executive function deficits are typical of Alzheimer's disease, whereas nonspecific or more variable performance is seen in major depression. Alternatively, treatment of the depressive disorder with repeated observation over time may be required to make the diagnosis.

Specific learning disorder and other neurodevelopmental disorders

A careful clarification of the individual's baseline status will help distinguish an NCD from a specific learning disorder or other neurodevelopmental disorders. Additional issues may enter the differential for specific etiological subtypes, as described in the relevant sections.

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