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A neurocognitive disorder meeting full criteria for a major or mild neurocognitive disorder, for which, despite a thorough workup, no specific underlying etiology can be identified or confirmed.
This diagnosis is used when someone's presentation clearly meets criteria for a major or mild neurocognitive disorder, but a thorough clinical, laboratory, and imaging workup does not identify a specific cause, and no single or multiple etiology can be confidently established. It is distinct from simply not having completed a workup -- it reflects genuine diagnostic uncertainty after appropriate evaluation.
Can occur at any age at which a neurocognitive disorder might present; the absence of an identified cause does not change the cognitive symptom pattern itself, which still requires meeting full neurocognitive disorder criteria.
Functional impact follows the severity of the cognitive impairment itself (major versus mild), independent of whether a cause has been identified.
This diagnosis may later be revised if further evaluation, disease progression, or new diagnostic tools eventually identify a specific etiology.
Access to the full range of diagnostic workup (advanced imaging, biomarker testing, genetic testing) varies substantially by setting and resources, which can affect how often this diagnosis is used appropriately versus as a placeholder for an incomplete evaluation.
A common misconception is that this diagnosis is simply used whenever a cause isn't immediately obvious; it specifically requires that a thorough workup has been completed without identifying a cause, not that the workup was skipped or is still pending.
Reconsider this diagnosis if the workup has not yet been completed, or if a specific etiology is subsequently identified through further evaluation or disease progression.
A 70-year-old man meets full criteria for a mild neurocognitive disorder, and despite comprehensive neuroimaging, laboratory testing, and biomarker evaluation, no specific etiology -- neurodegenerative, vascular, or otherwise -- can be identified.
Know
Know that this diagnosis requires a thorough, completed workup that nonetheless fails to identify a cause, not simply an absence of testing.
Notice
Notice that this diagnosis may be revised later if new evaluation or disease progression eventually reveals a specific etiology.
Distinguish
Distinguish from Neurocognitive Disorder Due to Multiple Etiologies by the absence, rather than the positive presence, of identifiable contributing causes.
Recognize
Full criteria for a major or mild neurocognitive disorder are met, but a thorough workup does not identify a specific etiology, and this is not attributable to an incomplete evaluation.
Distinguish
Distinguish from Neurocognitive Disorder Due to Multiple Etiologies by the absence, rather than the positive presence, of identifiable contributing causes.
Neurocognitive Disorder Due to Multiple Etiologies (used when there is positive evidence for more than one cause, a different situation from no identified cause at all), any specific-etiology neurocognitive disorder for which the workup was incomplete (this diagnosis should not be used as a substitute for pursuing an appropriate, thorough workup when one has not yet been completed), Delirium or another reversible condition that has not yet been adequately ruled out.
Clinicians may default to 'multiple etiologies' when they are simply uncertain, when 'unknown etiology' would be more accurate if no single cause has actually been confirmed — the two labels carry different evidentiary standards.
Unknown Etiology NCD is sometimes conflated with Unspecified NCD, but they reflect different situations: Unknown Etiology follows a completed, thorough workup that simply didn't find a cause, while Unspecified reflects insufficient information or an incomplete workup.
Unspecified Neurocognitive Disorder is sometimes assumed to be a lesser or vaguer diagnosis than NCD Due to Unknown Etiology, when in fact it requires the same careful assessment, with the added step of documenting the specific reason full criteria were not met.
Reason
Apply
Apply the evidentiary distinction between NCD Due to Unknown Etiology and NCD Due to Multiple Etiologies.
Distinguish Unspecified Neurocognitive Disorder (workup not yet done) from NCD Due to Unknown Etiology (thorough workup completed, no cause found) and from delirium.
Retrieve
2 question(s) reference this disorder. Practice Neurocognitive Disorder Due to Unknown Etiology →
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