WHy study Neurocognitive disorders
- Common disorders, particularly prominent in adulthood, esp towards older adulthood (contrasts with early developmental disorders)
- An interesting suite of disorders within the DSM
context - An exemplar for highlighting ethical issues
Are neurocognitive disorders common?
The answer is yes, but umbrella term (NCD)
is not useful in this context
- Our two exemplars, neurocognitive disorder due to Alzheimer’s disease or delirium are very common in older people
When do neurocognition disorders usually appear?
NCDs tend to first appear around age 50–60 years. The
number of people experiencing NCDs rapidly accelerates after the age of 70 years
How common is delirium?
Present in approx. 10 – 15% of people who come into acute care facilities such as ER
- Associated with increasing age
- Associated with substance use or other illnesses (due to general medical condition or substance-induced delirium
What is a point of contrast about NCDs in the DSM (why are they included in the DSM)
- The neuropathological or biological component of the NCDs is arguably stronger than for other disorders; [disorders that are closer to the DSM ‘dream’?]
- The NCDs give primacy to cognitive features; these
features may be present but less prominent in other
disorders. - Many NCDs are neurodegenerative
**The reason neurocognitive disorders (NCDs) are in the DSM is because they involve problems with thinking and memory that are the main cause of the disorder.
In other mental disorders (like depression or OCD), a person’s thinking can also be affected, but that’s not the main issue — it’s a secondary effect of mood or other symptoms.
What is unique about NCD’s in the DSM
For the NCDs, the diagnostic criteria refer to different things or weigh/consider other types of information, such as medical tests and normative reference points. we really don’t see that approach for other conditions.
How were NCD’s previously conceptualised and how are they conceptualised now?
previous thinking
–> organic mental disorders (believed to have pathology in the brain that gave rise to change in behaviour/function)
–> functional mental disorder (says its not really biologically based, it is change in our function/behaviour due to our psychological factors such as cognitions, behaviour)
Current thinking
All mental illness may have some degree of organicity
In the DSM-4 how was NCD’s framed
Primary impairment in Memory/ language/ attention/ consciousness
Delirium
Dementia
Amnestic disorders
Cognitivedisorders NOS
In the DSM-5 how was NCD’s framed (how did it change)
Introduced a new hierarchy:
Neurocognitive Disorders (NCDs) – main category.
Subtypes:
Delirium (stands alone).
Mild NCD (new category).
Major NCD (formerly “dementia”).
The diagnosis starts by identifying a primary impairment in cognition (memory, language, attention, thinking, etc.).
Then decide:
→ Is it mild or major disruption?
After that, add a specifier for cause (aetiology):
e.g. “Mild NCD due to Alzheimer’s disease,”
“Major NCD due to Parkinson’s,”
Can also add behavioural specifiers (if behavioural disturbance present):
e.g. wandering, hallucinations, aggression.
Can include severity and probability specifiers (how certain we are about the cause — e.g. “probable” vs “possible” Alzheimer’s).
DSM-5-TR also added stimulant-induced mild NCD as a new form
Key new features of NCD in DSM 5
Mild NCD was newly introduced and controversial:
Based on the research term mild cognitive impairment (MCI).
Added to capture early cognitive decline that isn’t yet dementia.
Critics argue it may blur the line between normal ageing and disorder.
What is The behavioural specifier when diagnosing a NCD
BPSD = umbrella term for non-cognitive symptoms/behaviours –> In Alzheimer’s, called Behavioural and Psychological Symptoms of Dementia (BPSD).
Used when neuropsychiatric symptoms are present.
Common across dementia types and settings (home & residential care)
Major source of caregiver burden.
Often difficult to treat with medication
What is Delerium? (criteria)
A. A disturbance in attention & awareness
B. The disturbance develops quickly, it represents a change,
the presentation fluctuates in 24-hr period
C. An additional disturbance in cognition
D. A & C are not explained by a pre-existing or emerging NCD
E. Evidence that disturbance is a direct physiological consequence of another medical condition
Criteria for a mild NCD
A. Evidence of modest decline, in ≥ 1 specified cognitive
domain based on
- Concern about mild decline from the individual, a knowledgeable informant, or the clinician AND
- A modest impairment in cognitive performance, preferably documented by neuropsychological testing, or in its absence, another quantified clinical assessment
B. The cog deficits do not interfere with everyday living, but greater effort may be needed (e.g., reminders).
C. Deficits are not in the context of delirium…
D. …or due to another mental disorder
Is the mild NCD subtype useful?
Mild NCD risks pathologising the “worried well” So why include it?
- Updates “predementia construct” (Bermejo-Pareja et al. 2022)*
- Provides early intervention point
But does it do this?
Not everyone “converts” from mild to major NCD due to AD:
* Approx 50% remain stable
* Small percentage “reverts” to “normal cognition”
Criteria for Major NCD
A. Evidence of significant decline, in ≥ 1 specified cognitive domains based on
* Concern about significant decline from the individual, a knowledgeable informant, or the clinician AND
* A substantial impairment in cognitive performance, preferably documented by neuropsychological testing, or in its absence another quantified clinical assessment
B. The cog deficits do interfere with everyday living; at a minimum including those that are more complex.
C. Deficits are not in the context of delirium…
D. …or another mental disorder
Diagnostic Approach
- Decided if the mild or major NCD are met
- Consider the neuropathology.
- Adjust the diagnosis “due to…” accordingly.
How do you know to diagnose probable or possible?
Probable is automatic when evidence of “causative” genetic mutation. Else probability depends on initial parsing (ie mild or major) & the nature & extent of cognitive decline
Probable AD: confirmed genetic mutation or clear, consistent clinical pattern.
Possible AD: clinical features fit, but no genetic confirmation or other uncertainty.
Serial testing required → to document objective cognitive decline over time.
Course: gradual onset and progressive worsening over years (distinguishes it from delirium, which has rapid onset).
Allen Francis opion on DSM mild NCD
“The every day forgetting characteristic of old age will now be misdiagnosed as Mild NCD, creating a huge false positive population of people who are not at special risk for dementia. Since there is no effective treatment for this ‘condition’ (or for dementia), the label provides absolutely no benefit (while creating great anxiety) even for those at true risk for later developing dementia”
Challenges of diagnosing NCDs
- Acquired vs developmental cognitive problems
NCD = acquired decline in cognition (a change from previous ability).
Must distinguish from developmental intellectual impairments (present since birth).
Sometimes both coexist → hard to separate developmental vs acquired causes - Overlap with other psychopathologies
Cognitive symptoms occur in many disorders (e.g. poor concentration in depression) - Reversible vs irreversible:
Must rule out reversible causes (e.g. medication, infection, vitamin deficiency) before diagnosing irreversible types (e.g. Alzheimer’s).
→ Diagnosis of exclusion - Differential diagnosis:
Delirium vs dementia: Delirium = sudden & fluctuating; Dementia = gradual, steady decline.
Depression vs dementia: Depression = short course, insight present; Dementia = gradual, poor insight
What are some Some ‘treatable’ causes of Major NCD
Medication or diet- related
e.g., long term, heavy alcohol use; Vitamin B12 deficiency
Secondary to other diseases
e.g., metabolic dysfunction from kidney, thyroid or liver
conditions
Structural impediments
e.g., operable brain tumour, hematoma, or vessel
blockage
Differential diagnosis between depression and delerium may be difficult because
- Symptoms overlap, especially given manifestation of depression in the elderly
- Comorbidity ( 25% of those with dementia also exhibit symptoms of major depressive disorder).
- The DSM-5 gives the impression of discrete dementia subtypes, but the neuropathology and clinical disorder presentation can be weakly correlated or mixed
Causes (Aetiology)
Depends on the type and location of brain pathology.
Use “due to” specifier (e.g. NCD due to Alzheimer’s, Parkinson’s, Huntington’s, TBI).
Some are genetic (e.g. Huntington’s), others not.
Often neurodegenerative → progressive, no cure.
Fewer psychological/social causes compared to other mental disorders.
Treatment Approach
If reversible cause: treat underlying issue (e.g. UTI causing delirium → antibiotics).
If irreversible: focus on
Medication based on underlying disease.
Goals: slow decline, manage symptoms, improve quality of life.
Support for caregivers and psychosocial management are essential.
AD research and medication
Current AD drugs: may slow decline but don’t stop the disease.
Focus on disease-modifying agents targeting amyloid plaques/tangles.
Ongoing research for earlier treatment/prevention (e.g. mild NCD stage).
Media hype often overstates progress → some drugs approved prematurely, causing controversy
