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Lyketsos CG, Lopez O, Jones B, Fitzpatrick AL, Breitner J, DeKosky S. Prevalence of Neuropsychiatric Symptoms in Dementia and Mild Cognitive ImpairmentResults From the Cardiovascular Health Study. JAMA. 2002;288(12):1475–1483. doi:10.1001/jama.288.12.1475
Context Mild cognitive impairment (MCI) may be a precursor to dementia, at least
in some cases. Dementia and MCI are associated with neuropsychiatric symptoms
in clinical samples. Only 2 population-based studies exist of the prevalence
of these symptoms in dementia, and none exist for MCI.
Objective To estimate the prevalence of neuropsychiatric symptoms in dementia
and MCI in a population-based study.
Design Cross-sectional study derived from the Cardiovascular Health Study,
a longitudinal cohort study.
Setting and Participants A total of 3608 participants were cognitively evaluated using data collected
longitudinally over 10 years and additional data collected in 1999-2000 in
4 US counties. Dementia and MCI were classified using clinical criteria and
adjudicated by committee review by expert neurologists and psychiatrists.
A total of 824 individuals completed the Neuropsychiatric Inventory (NPI);
362 were classified as having dementia, 320 as having MCI; and 142 did not
meet criteria for MCI or dementia.
Main Outcome Measure Prevalence of neuropsychiatric symptoms, based on ratings on the NPI
in the previous month and from the onset of cognitive symptoms.
Results Of the 682 individuals with dementia or MCI, 43% of MCI participants
(n = 138) exhibited neuropsychiatric symptoms in the previous month (29% rated
as clinically significant) with depression (20%), apathy (15%), and irritability
(15%) being most common. Among the dementia participants, 75% (n = 270) had
exhibited a neuropsychiatric symptom in the past month (62% were clinically
significant); 55% (n = 199) reported 2 or more and 44% (n = 159) 3 or more
disturbances in the past month. In participants with dementia, the most frequent
disturbances were apathy (36%), depression (32%), and agitation/aggression
(30%). Eighty percent of dementia participants (n = 233) and 50% of MCI participants
(n = 139) exhibited at least 1 NPI symptom from the onset of cognitive symptoms.
There were no differences in prevalence of neuropsychiatric symptoms between
participants with Alzheimer-type dementia and those with other dementias,
with the exception of aberrant motor behavior, which was more frequent in
Alzheimer-type dementia (5.4% vs 1%; P = .02).
Conclusions Neuropsychiatric symptoms occur in the majority of persons with dementia
over the course of the disease. These are the first population-based estimates
for neuropsychiatric symptoms in MCI, indicating a high prevalence associated
with this condition as well. These symptoms have serious adverse consequences
and should be inquired about and treated as necessary. Study of neuropsychiatric
symptoms in the context of dementia may improve our understanding of brain-behavior
Dementia is a serious public health problem with an increasing prevalence
because of the aging of the population.1 Dementia
is characterized by global cognitive decline sufficient to affect functioning.2 It is a chronic illness with seriously disabling effects
for patients, their families, and society.2
Mild cognitive impairment (MCI) describes cognitive impairment in elderly
persons not of sufficient severity to qualify for a diagnosis of dementia.3 Individuals with MCI have complaints of impairment
in memory or other areas of cognitive functioning usually noticeable to those
around them. In addition, their performance on memory and cognitive tests
is below that expected for their age and education. However, their day-to-day
functioning is generally preserved. Several operational definitions for MCI
have been proposed.3,4 Mild cognitive
impairment is a chronic condition and may be a precursor to Alzheimer-type
dementia.4 Mild cognitive impairment is often
worrisome to patients and families, and is increasingly a presenting complaint
Neuropsychiatric symptoms are a common accompaniment of dementia.5,6 These include agitation, depression,
apathy, delusions, hallucinations, and sleep impairment. In some cases, they
cluster into syndromes, leading to the proposal of operational criteria for
specific dementia-associated psychotic7,8
or mood disturbances.8,9 These
symptoms have serious adverse consequences for patients and caregivers, such
as greater impairment in activities of daily living,10
more rapid cognitive decline,11 worse quality
of life,12 earlier institutionalization,13 and greater caregiver depression.14
Thus, the neuropsychiatric accompaniments of dementia are serious conditions
that are increasingly becoming a focus of attention.
Several studies have estimated the prevalence of the neuropsychiatric
symptoms of dementia. Depending on the method, it has been estimated that
they affect 50% to 80% of persons with dementia in the course of the disease.2,15 The vast majority of studies were
conducted in a clinical setting subject to referral bias that might overestimate
the prevalence of neuropsychiatric symptoms.
Only 2 population-based studies have assessed the prevalence of neuropsychiatric
symptoms in dementia. The first was conducted in England more than a decade
ago and focused only on Alzheimer-type dementia.16-19
A more recent US study20 estimated that in
the month before examination 61% of participants with dementia exhibited 1
or more of these symptoms. Apathy (27%), depression (24%), and agitation (24%)
were the most common. Because this study was conducted in Utah in a rather
homogeneous population, concerns have been raised about its generalizability.
There are additional limitations to the population studies of neuropsychiatric
symptoms in dementia. First, there has not been a replication of the US estimate.
Second, neither study investigated the prevalence of clinically significant
symptoms. Third, only the England study estimated the prevalence of symptoms
from the onset of cognitive impairment. Fourth, neither study estimated the
prevalence of symptoms involving sleeping or eating, both of which are now
recognized in clinical settings as being of importance.
No study has assessed the prevalence of neuropsychiatric symptoms in
MCI. Such an estimate is important for several reasons. The current definitions
of MCI do not mention these symptoms, thus an estimate of prevalence might
have definitional implications. Moreover, if MCI is a precursor to Alzheimer-type
dementia, the prevalence of neuropsychiatric symptoms in MCI should be intermediate
to that in cognitively healthy individuals and in persons with dementia. Such
a finding would have implications for the understanding of the pathophysiology
of these symptoms in both MCI and dementia.
We undertook the present analyses as part of the Cardiovascular Health
Study (CHS) Cognition Study. We sought to estimate the prevalence of neuropsychiatric
symptoms, including clinically significant symptoms, in the past month in
a population-based panel of persons with dementia, including the prevalence
of sleep and eating disturbances; neuropsychiatric symptoms, including clinically
significant disturbances, in the past month in MCI; and neuropsychiatric symptoms
from the onset of cognitive impairment in MCI or dementia.
The CHS and its methods have been described in detail elsewhere.21-23 This is a cohort
study of individuals at least 65 years old randomly sampled from Medicare
lists in 4 US communities, each site overseen by researchers at a nearby university.
The communities include Washington County, Maryland (Johns Hopkins University),
Forsyth County, North Carolina (Wake Forest University), Allegheny County,
Pennsylvania (University of Pittsburgh), and Sacramento County, California
(University of California at Davis). A total of 5201 participants were recruited
in 1989-1990 and an additional 687 blacks were enrolled in 1992-1993. The
institutional review board at each university approved the study, and each
participant gave informed consent. Participants completed between 1 and 10
annual clinic visits until 1998-1999. Loss to follow-up in CHS, other than
through death, was very low (<5%). The original aims of the CHS were to
assess risk factors in elderly persons for cardiovascular outcomes, including
angina, myocardial infarction, cardiac death, and stroke.
Data collected longitudinally at each annual visit included information
on medical history, blood pressure, medications, physical function, social
support, depression, and cognition using the Modified Mini-Mental State Examination,24 which is a cognitive battery widely used in epidemiologic
studies, and the Digit Symbol Substitution Test.25
If an individual did not receive a clinical evaluation, then attempts were
made to evaluate cognition using the Telephone Interview for Cognitive Status.26 For participants who died between examinations, we
obtained further information using the Informant Questionnaire for Cognitive
Decline in the Elderly27 and data concerning
circumstances of death. The CHS also collected information for all hospitalizations,
including a review of medical records and selected laboratory and clinical
Between 1991-1994, 3660 participants received cerebral magnetic resonance
imaging (MRI). Differences between those who completed the scan and those
who did not have been reported elsewhere.28
Of the 3660, 3608 participants who completed a Modified Mini-Mental State
Examination at the time of the MRI were designated for inclusion in the CHS
Cognition Study (Figure 1). Of those
who had an MRI, 1492 screened negative for dementia based on the screening
procedure that was used. Of the remaining 2116, 707 were classified as having
dementia, 577 as MCI, 826 as being cognitively healthy, and 6 unknown based
on the CHS Cognition Study evaluation procedures. A subset of participants
with dementia (n = 362) or MCI (n = 320) agreed to be rated on the Neuropsychiatric
Inventory (NPI) and constitute the study sample for these analyses.
Fieldwork for the CHS Cognition Study, designed to evaluate dementia
in a subset of CHS participants, was implemented during 1999-2000. Lopez et
al29 present further detail on the CHS Cognition
Study. In brief, investigators performed a multistage screening and evaluation
process on all eligible participants. In the first stage, participants were
classified as being at low or high risk for dementia (risk screening), based
upon previous cognitive testing during CHS clinic visits and medical history.
Using data already collected, individuals at 3 of the centers deemed to be
at high risk for dementia, of minority race, or having only limited cognitive
data were identified for further evaluation. At 1 center (University of Pittsburgh),
attempts to collect additional data were made on all participants regardless
of risk. High risk for dementia was based on previous cognitive testing, changes
in cognitive scores, nursing home admission, and history of stroke. High risk
was defined as a Modified Mini-Mental State Examination score of less than
80 at 1 of their last 2 clinic visits in the study, a 5-point decline in the
Modified Mini-Mental State Examination score from the time of MRI to last
contact, a Telephone Interview for Cognition Status score of less than 28
or an Informant Questionnaire for Cognitive Decline in the Elderly score of
more than 3.6, an incident stroke, a medical record review recording dementia,
or currently residing in a nursing home. Individuals at high risk were recruited
for neuropsychological testing. For participants who refused the neuropsychological
battery, we collected data from medical records, physician questionnaires,
and participant and proxy telephone interviews.
Participants identified for neuropsychological testing underwent a full
battery, including tests of premorbid intelligence, memory, language, visuoperceptual
and visuoconstructional ability, executive functions, and motor function.
The test results of the neuropsychological testing were classified as normal
or abnormal by age and levels of education using data that were collected,
primarily, from a sample of 250 nondemented controls at the Univeristy of
Pittsburgh center, where all available participants underwent further evaluation.
At the other 3 centers, participants with abnormal tests of memory or of any
2 other domains underwent further evaluation.
Additional evaluation was completed by a neurologist or geriatric psychiatrist
and involved a neurological examination and completion of the NPI,30 a widely used measure of the presence of severity
of neuropsychiatric symptoms in dementia. An interview with the participant's
proxy was also done using the Dementia Questionnaire.31
Using all information, classification of dementia, MCI, or healthy was made
locally. The diagnosis of dementia was based on progressive cognitive decline
or static cognitive deficit of sufficient severity to affect the participants'
activities of daily living, and history of healthy intellectual function before
the onset of cognitive abnormalities. Patients were required to have impairments
in 2 cognitive domains, which did not necessarily include memory.
All information was sent to the University of Pittsburgh center regardless
of the diagnoses by the local neurologist or psychiatrist. A neurologist with
extensive experience in dementia reviewed all cases from every center and
reclassified these as dementia, MCI, or healthy. All cases classified as possible
dementia locally or at the review were then reviewed by an adjudication committee
composed of study neurologists and psychiatrists from all 4 CHS clinics.
Classification was based on Diagnostic and Statistical
Manual of Mental Disorders, Fourth Edition (DSM-IV)32
for dementia and National Institute for Neurologic Diseases and Stroke, Alzheimer
Disease and Related Disorders Association33
for Alzheimer-type dementia. Based on results from the University of Pittsburgh
center, in which all participants (rather than only high-risk participants)
underwent full evaluation, we estimated that overall rates of dementia were
about 9% lower than if all participants at all 4 centers were evaluated.
Mild cognitive impairment was defined as cognitive decline not meeting DSM-IV criteria for dementia.32
It was operationalized using results of neuropsychological testing in 2 groups
as follows, with both groups considered as one in this study34:
(1) MCI amnestic-type: participants with isolated progressive or static memory
deficits (delayed-recall verbal memory, nonverbal memory, or both) defined
as a score on a standardized test that was 1.5 SD below the mean compared
with individuals of the same age and level of education (other tests were
healthy); and (2) MCI multiple cognitive deficits-type: participants with
a progressive or static deterioration in at least 1 cognitive domain (not
including memory), or 1 abnormal test (1.5 SD below the mean adjusted for
age and education) in at least 2 other domains, but who had not crossed the
threshold for dementia.
We used the NPI30 to define the presence
and severity of neuropsychiatric symptoms. The NPI has wide acceptance as
a measure of neuropsychiatric symptoms associated with cognitive disorders.35 It rates symptoms in 12 domains: delusions, hallucinations,
agitation/aggression, depression, anxiety, euphoria, apathy, disinhibition,
irritability, aberrant motor behavior, sleep, and eating. It is a fully structured
interview, which obtains its information from an informant knowledgeable about
the participant, and it focuses on observable symptoms and behaviors. Within
each domain, NPI asks a screening question. If the screening question is answered
in the negative, the interviewer moves to the next domain. If it is answered
in the affirmative, specific neuropsychiatric symptoms are assessed within
each domain. If any of these symptoms are present, they are rated on a 4-point
frequency scale and a separate 5-point severity scale. The product of the
frequency and severity scales within each domain produces a total domain score
(range, 0-20). Individual domain scores are summed to produce a total NPI
score. Domain scores of 4 or more or total NPI scores of 4 or more are indicative
of clinical significance and are used as entry criteria for treatment trials
of dementia-associated neuropsychiatric symptoms.36
In the clinical setting, such scores are associated with need for an intervention
to manage the symptoms.
Informants were also asked to note whether neuropsychiatric symptoms
had occurred from the onset of cognitive symptoms. The severity of symptoms
before the past month was not rated due to concerns that the reliability of
such ratings would be low.
The NPI was completed on 824 participants, 362 of whom were ultimately
classified as having dementia and 320 classified as having MCI. A total of
142 were rated after the first-phase screening process because of cognitive
decline or subnormal cognitive functioning but did not meet criteria for MCI
or dementia. This was a sample biased toward individuals with cognitive disturbance
of insufficient severity to meet criteria for MCI or dementia. Rates of neuropsychiatric
symptoms in this group would not be representative of other cognitively healthy
elderly persons; hence, NPI findings from this group were not considered in
the analyses. The NPI was also used in the Cache County Study,20
permitting comparisons of the 2 studies.
Analyses compared participants with dementia to those with MCI and to
published data on NPI symptoms from cognitively healthy elderly persons.20 We compared symptoms in the past month between the
study groups with a frequency distribution of the number of individual symptoms.
Then, we compared the prevalence of any 1 symptom in the past month. In these
analyses, we separated mild symptoms within each domain (NPI score = 0-3)
from clinically significant symptoms (NPI score = 4). These frequencies were
compared using χ2 tests.
We then compared the prevalence of individual NPI symptoms from the
onset of cognitive symptoms between the dementia and MCI groups. These comparisons
were made for the presence of any disturbance, regardless of severity, because
we did not have severity ratings to differentiate mild disturbances from clinically
significant disturbances. These frequencies were also compared using χ2 tests.
Finally, to assess whether there were differences in NPI symptom prevalence
between Alzheimer-type dementia and other dementia, we compared the prevalence
of NPI symptoms in the past month in participants with Alzheimer-type dementia
with participants with other types of dementia, using χ2 tests.
Statistical analyses were performed using SPSS version 10 (SPSS Inc, Chicago,
Ill) and P<.05 was the level of significance.
Table 1 shows demographic
characteristics of the study groups. As expected, those with dementia were
older than those with MCI. Among younger participants (mean age and below),
those with dementia were less likely to be black compared with those with
MCI. There was no difference in sex frequency between the groups and the 2
groups had comparable education.
Figure 2 displays a frequency
distribution of the number of NPI symptoms in the past month in the 2 study
groups, as well as the mean (SD) of each distribution. There was an increase
in the number of symptoms from MCI to dementia. Slightly more than half the
MCI participants exhibited no neuropsychotic symptoms. In contrast, only a
minority of dementia participants were symptom free. About 55% of the dementia
participants reported 2 or more, and 44% reported 3 or more symptoms.
Table 2 compares the prevalence
of individual NPI symptoms in the past month by group. We report rates for
any symptom (NPI >0), for clinically significant symptoms (NPI ≥4) by domain,
and for the NPI as a whole. Using χ2 tests, the 2 groups were
compared on the proportion of participants in each group with NPI scores of
0, 1-3, or 4 and higher. Table 2
also includes prevalence estimates for individual NPI symptoms (NPI >0) in
cognitively healthy participants from the Cache County Study.20
Approximately 75% of participants with dementia exhibited 1 or more NPI symptoms,
with 62% clinically significant. Participants with MCI had lower rates, with
43% exhibiting any 1 symptom and 29% exhibiting clinically significance. There
was an incremental increase in frequency of neuropsychiatric symptoms across
groups. As expected, the lowest frequency was observed in cognitively healthy
participants, intermediate frequency in MCI, and highest frequency in dementia.
In all cases, the prevalence of NPI symptoms was significantly higher in participants
with dementia than in those with MCI.
Among participants with dementia, the most frequent symptom was apathy
(36%), followed by depression (32%), and agitation/aggression (30%). Apathy
was the most frequent clinically significant (disturbance score ≥4) neuropsychiatric
symptom, followed by sleep disturbance and depression. Most symptoms present
were clinically significant.
In the MCI group, the frequency of most symptoms was intermediate between
the cognitively healthy comparison population and the dementia participants.
The most frequent symptom was depression (20%), followed by apathy (15%) and
irritability (15%). The most frequent clinically significant symptom (disturbance
score ≥4) was sleep disturbance (8.8%), followed by irritability (7.5%),
depression (6.3%), apathy (6.3%), and eating disturbance (6.3%). Using χ2 tests, the rate of neuropsychiatric symptoms in MCI was compared with
that among nondemented elderly persons from the Cache County Study, using
the published data from the latter study. Given that multiple comparisons
were made, we applied the Bonferroni adjustment requiring an α of .001
for statistical significance. The prevalence of any 1 symptom was significantly
higher in the MCI participants of CHS than in the elderly population of the
Cache County Study (χ21 = 81.2, P<.001). When individual disturbances were compared, the prevalence
among MCI participants in the CHS was significantly higher for agitation/aggression
(χ21 = 26.5, P<.001),
depression (χ21 = 33.5, P<.001),
apathy (χ21 = 41.7, P<.001),
irritability (χ21 = 28.6, P<.001),
and aberrant motor behavior (χ21 = 13.2, P<.001). Differences between the 2 groups were of marginal significance
for anxiety (χ21 = 3.65, P
= .06) and disinhibition (χ21 = 5.17, P = .02), and not significant for delusions, hallucinations, or euphoria
(in all cases, P>.51). Euphoria was rare in all 3
groups, as expected.20,37
Eighty percent of dementia participants and almost 50% of MCI participants
exhibited at least 1 NPI symptom from the onset of cognitive symptoms (Table 3). Apathy and depression were the
2 most common, followed by agitation/aggression. The prevalence of delusions
or hallucinations was lower than the most common symptoms. In all cases, there
was a significant increase in prevalence from MCI to dementia. The meaning
of these data is uncertain because there are no published estimates of the
cumulative prevalence of NPI symptoms in cognitively healthy elderly persons
aged 65 or older from the Cache County Study or elsewhere. However, the prevalence
rates in Table 3 for neuropsychiatric
symptoms in both MCI and dementia are much higher than past-month population
estimates from the Cache County Study (Table 2) and prevalence estimates for specific mental disorders
from the US Epidemiologic Catchment Area study (anxiety disorders, 5.5%; affective
disorders, 2.5%; schizophrenia, 0.1%).35
Table 4 contains the prevalence
of symptoms in the past month among participants with National Institute for
Neurologic Diseases and Stroke, Alzheimer Disease and Related Disorders Association33 probable or possible Alzheimer disease compared with
those with other dementia. Of the 104 participants with non-Alzheimer disease
dementia, the expert consensus panel concluded that 86 had vascular dementia,
and 6 had dementia due to Parkinson disease. The remaining 12 had a range
of different types of dementia etiologies, such as postanoxic dementia, posttraumatic
dementia, frontotemporal degeneration and others. Table 4 compares the frequency of mild symptoms with clinically
significant symptoms. There were no significant differences between participants
with Alzheimer-type dementia and those with other dementia, with the exception
of aberrant motor behavior (P = .02).
These findings confirm previous estimates of high prevalence of neuropsychiatric
symptoms in dementia, with 60% of participants with dementia exhibiting clinically
significant symptoms in the past month, and more than 80% exhibiting any symptom
from the onset of cognitive impairment. Apathy, depression, and agitation
were the most frequent. We also report estimates for sleep and eating disturbances,
which have not been previously reported. Prevalence estimates were similar
in Alzheimer and non-Alzheimer dementia, with the exception of more aberrant
motor behavior in Alzheimer-type dementia, consistent with clinical reports
that wandering is more frequent in Alzheimer-type dementia.38
Our findings confirm that the majority of neuropsychiatric symptoms in dementia
are of clinical significance based on their severity and because of co-occurrence
of multiple symptoms with more than half of participants with dementia exhibiting
2 or more neuropsychiatric symptoms in the past month.
We report the first population-based estimates to our knowledge of neuropsychiatric
symptoms in MCI. This is a group of individuals with cognitive impairment
not severe enough to warrant a diagnosis of dementia. Recent evidence suggests
that many, if not most, eventually develop Alzheimer-type dementia,4 so that MCI is a precursor syndrome to dementia. The
finding that neuropsychiatric symptoms in MCI have a prevalence intermediate
to that in healthy participants and those with dementia, further supports
this hypothesis. Mild cognitive impairment may not be a separate category
of disturbance, such as age-associated or age-appropriate memory loss, but
is rather on a continuum between healthy and dementia.
These estimates are comparable with those reported in the other 2 population-based
Thus, the epidemiologic evidence supports the findings from clinical studies5,15 indicating that neuropsychiatric symptoms
afflict almost all patients with dementia over the course of their illness.
Similarly, neuropsychiatric symptoms afflict almost 50% of patients with MCI.
Our study limitations include the sampling method in that the participants
with dementia were ascertained from the members of an original random sample
of elderly individuals in 4 communities who agreed to have an MRI. Those examined
were oversampled for the presence of stroke, minority status, and unknown
cognitive scores. Thus, the original sampling frame was not fully representative
of the population and may have biased the prevalence estimates for NPI symptoms
among those with dementia and MCI. However, any such bias would be systematic
and lead to an underestimate of the prevalence of disturbance. A second limitation
was that the NPI, while reliable and valid, did not directly evaluate participants
but rather relied on information obtained from an informant interview. Results
may have been different if a clinical diagnosis of neuropsychiatric symptoms
had been used. However, the agreement between this study and studies where
clinical evaluations were used is reassuring.16-19
What is the significance of the high prevalence of neuropsychiatric
symptoms in dementia and MCI? It supports the status of MCI as an intermediate
condition between healthy cognition and dementia. With regard to dementia,
there are 2 notable implications. The first involves the pathophysiology of
neuropsychiatric symptoms in dementia. These disturbances may be the consequences
of damage to the brain brought about by underlying brain disease. For example,
in Alzheimer disease, delusions have been associated with parietal hypoperfusion
on single-photon emission computed tomography,39
depression with damage to noradrenergic or serotonergic brain nuclei,40-43 and
aggression with damage to serotonergic nuclei in the context of relative preservation
of dopaminergic brain areas.44,45
Thus, the study of neuropsychiatric symptoms in dementia offers an opportunity
for further understanding of brain-behavior relationships. Studies have focused
on clinical pathologic correlations using brain imaging or neuropathology.
Recent advances will also allow us to add genomic study to estimate the modifying
effect of genes on the expression of neuropsychiatric symptoms. Already evidence
exists for a link between Alzheimer-type dementia–associated psychosis
and genetic variation in dopamine receptors.46
The second implication relates to the treatment of patients with MCI
and dementia. Neuropsychiatric symptoms compound the disability of patients
and are increasingly a target of treatment. Nonpharmacological interventions
have efficacy for mild disturbances.47 Controlled
clinical trials have reported efficacy of antipsychotics for agitation or
antidepressants for depression,52-55
anticonvulsants for agitation,56,57 β-adrenergic
blockers for aggression,58 and cholinesterase
inhibitors for behavioral symptoms.59-61
Careful recognition and appropriate treatment of the neuropsychiatric symptoms
associated with MCI and dementia is likely to provide substantial benefits
to patients and caregivers.2 Dementia and MCI
continue to be poorly recognized in primary care,62
and neuropsychiatric symptoms are often not recognized until they have become
severe leading to hospitalization or institutionalization.
In summary, these findings further confirm the high prevalence of neuropsychiatric
symptoms in dementia and indicate a moderate prevalence in MCI. Clinical evaluations
of patients with suspected MCI and dementia must include specific assessment
of and treatment for such symptoms. This also has significant implications
for further studies of the pathophysiology and treatment of neuropsychiatric
symptoms in cognitively impaired elderly people.