Depression and Dementia

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Depression and Dementia
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Epidemiology

• Overall findings
• Depression present in about 20-40 of dementia
  patients
• Rate is about 4 times that of the normal
  population
• Less common in AD, more common in other dementias
  (subcortical, vascular)
• US 25-30 of vascular dementia, 15-20 of AD
• US as high as 75 of dementia patients report
  at least 1 symptom in previous month, most common
  being depression, apathy and irritability

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Epidemiology (cont.)

• In AD, incidence of depression within 5 yrs
  before or after onset is increased
• 15-20 of AD patients have depression
• May not be true when comparing depression rates
  in institutional settings
• Also an early symptom in DLB

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Epidemiology (cont.)

• Depression in vascular dementia
• Higher than in AD
• Highest in 1st year with single stroke
• Increases with MID
• Vascular dementia/depression rates especially
  high with periventricular lesions also have
  other executive functioning deficits (40 rate)

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Epidemiology (cont.)

• Comorbidity/confusion with substance abuse,
  anxiety
• Effects
• Depression associated with more functional
  impairment
• Depression associated with higher morbidity in
  late stages of dementia
• Depression associated with onset of dementia in
  AD associated with more rapid course

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Epidemiology (cont.)

• History
• In middle age, there is a relationship between
  depression and memory complaints, but this
  relation does not hold in people with the AD ApoE
  high-risk subtype
• ApoE high-risk subtype not a predictor for
  depression in AD
• Debated link between family/personal history of
  depression and occurrence of MD in AD
• High mortality rates in people with greater
  pre-dementia cognitive reserve and depression

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Epidemiology (cont.)

• Rates of depression in PD with or without
  dementia and DLB similar
• Depression rates increase as death approaches
  depression within 6 months of death substantially
  underdiagnosed and undertreated (in demented and
  nondemented)
• Presence of late-onset depression doubles risk
  for dementia
• Patients with lower education and higher
  premorbid neuroticism may be at higher risk for
  depression in dementia

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Symptom Patterns

• Most overlap is between subcortical dementia and
  depression
• Depression with dementia
• Much more likely to be delusional
• More likely to have accompanying disorientation
• Depression patients more likely to display social
  adjustment problems

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Symptom Patterns (cont.)

• Dementia patients display more negative symptoms,
  e.g. avolitionality, apathy, fatigue, emotional
  disengagement and fewer (?) mood symptoms
• Possibly responds to treatment with atypical
  antipsychotics (e.g. risperidone)
• Negative symptoms can occur without the presence
  of depression
• Negative symptoms associated with more cognitive
  and functional impairment, less insight

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Symptom Patterns (cont.)

• Memory performance in AD compared to MD
• Less benefit from multiple exposure to task
• More false positive errors
• More encoding problems, so poorer recognition
  memory
• Poorer at visuospatial associative learning
• For identification criteria see Olin, J., Katz,
  I., Meyers, B., Schneider, L., Lebowitz, B.
  (2002). Provisional diagnostic criteria for
  depression of Alzheimer disease Rationale and
  background. Am J Geriatric Psychiatry, 10(2),
  129-141.

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Symptom Patterns (cont.)

• Course
• Mood problems tend to increase over time with
  MID-type vascular dementia
• Higher level of functional impairment in vascular
  dementia that AD even when level of depression is
  controlled--more attentional problems
• Depression with vascular dementia more likely to
  respond to antidepressants that AD depression
• Mood problems and life satisfaction decrease then
  increase in AD
• Depression related to physical/verbal aggression
  and spontaneous disruptive verbalization in
  demented nursing home patients

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Symptom Patterns (cont.)

• Depression usually causes selective cognitive
  impairments (e.g. attention, memory) rather than
  global cognitive decline
• Early AD signs, low linguistic abilities,
  episodic memory problems language problems less
  common in depression
• Strong relationship between depression and degree
  of memory impairment in PD

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Theories

• Depression is a risk factor for AD, through one
  of several possible mechanisms
• It is an early prodrome
• It exacerbates symptoms so they clinically
  manifest
• In causes hippocampal damage through
  glucocorticoids
• See for instance Jorm, A. F. (2000). Is
  depression a risk factor for dementia or
  cognitive decline? A review. Gerontology, 46,
  219-227
• Note even if it is an early sign of dementia it
  should be treated! Verbal abilities recover
  better than nonverbal ones
• Seems especially to hold in late onset depression

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Theories (cont.)

• Best article probably Jorn, A. (2000). Is
  depression a risk factor for dementia or
  cognitive decline? A review. Gerontology, 46(4),
  pp. 219-227. Results of meta-analysis
• Depression is a risk factor for later dementia
• Risk factors for depression and dementia appear
  to be different
• Connection possibly due to one of the following
• Depression is a dementia prodrome
• Depression is an early reaction to cognitive
  problems
• Depression alters threshold for manifesting
  depression
• Depression is a causal factor

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Theories (cont.)

• Depression is a complication of vascular dementia
• Depression can mimic the effects of dementia but
  is actually unrelated (pseudodementia) this at
  odds with the predictor/risk factor hypothesis
  according to some
• Depression occurs as an independent psychiatric
  syndrome during the course of dementia

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Theories (cont.)

• A common process causes AD and MD in a subset of
  AD patients (Heun et al., 2002)
• Might be related to inflammatory processes that
  affect the immune system
• Leonard, B. (2001). Changes in the immune
  system in depression and dementia Causal or
  co-incidental effects? International Journal of
  Developmental Neuroscience, 19(3), pp. 305-312.
• But you can have cognitive impairment in
  depressed patients without sign of organic
  pathology, and this impairment improves with
  decreasing depression (but still not to level of
  depressed that had no cognitive complaints in the
  first place

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Theories (cont.)

• Depression accelerates functional disability from
  dementia
• Lower memory scores in depressed AD compared with
  nondepressed AD
• Depression results from functional disability in
  dementia
• Improvement in functioning through cognitive
  rehab leads to decreased depression scores
• But depression independent of dementia in nursing
  home patients

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Theories (cont.)

• A common process might cause subcortical
  dysfunction and depression
• There is a collinearity between EPS in normal
  older adults and depression (I.e. the same things
  predict each in similar ways

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Testing

• Need to watch comorbidity/confusion between
  depression and other medical conditions,
  especially if assessing in nursing home settings
• Interview data important
• Helpful tests include
• Dementia screening devices
• Depression inventories
• Neuropsychological tests and procedures

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Specific Tests

• HRSD
• Need separate cutoffs for different disorders
  highest for PD, lowest for AD.
• Naarding, P., Leentjens, A., van Kooten, F.,
  Verhey, F. (2002). Disease-specific properties
  of the Hamilton Rating Scale for Depression in
  patients with stroke, Alzheimer's dementia, and
  Parkinson's disease. Journal of Neuropsychiatry
  Clinical Neurosciences, 14(3), pp. 329-334.
• Overall optimum cutoff score was 10 in Israeli
  sample
• Geriatric Depression Scale, including short forms
• Folstein Mini-Mental State Exam (MMSE)

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Specific Tests (cont.)

• Clock drawing
• Accuracy around 80
• May not be better than MMSE
• See e.g. Shulman, K. I. (2000). Clock-drawing is
  it the ideal cognitive screening test? Int J
  Geriatr Psychiatry, 15, 548-561
• Smell identification
• Poor identification of odors (0 or 1 out of 3)
  discriminated 95 of AD patients from MD.
• Duff, K., McCaffrey, R., Solomon, G. (2002).
  The Pocket Smell Test Successfully
  discriminating probable Alzheimer's dementia from
  vascular dementia and major depression. Journal
  of Neuropsychiatry Clinical Neurosciences,
  14(2), pp. 197-201

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Specific Tests (cont.)

• The standard Stroop
• The emotional Stroop
• Depressed people had more slowing to color naming
  of negative emotion words that AD patients
• Dudley, R., O'Brien, J., Barnett, N., McGuckin,
  L., Britton, P. (2002). Distinguishing
  depression from dementia in later life A pilot
  study employing the emotional stroop task.
  International Journal of Geriatric Psychiatry,
  17(1), pp. 48-53.
• Williams J MG, Mathews A, MacLeod C. 1996. The
  Emotional Stroop task and psychopathology.
  Psychological Bulletin, 120 3-24

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Specific Tests (cont.)

• Memory tests that provide repeated trials,
  measure intrusions and encoding/recognition
  memory (e.g. CVLT)
• Information from both patient and caregiver
  patient information is generally helpful and
  reliable, but may tend to underrepresent the
  severity of the problem
• There is a relation between premorbid subjective
  memory complaints and later dementia, but the
  proportion with complaints who actually develop
  it is small so this isnt clinically useful

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Specific Tests (cont.)

• If depression has psychomotor retardation
  component, will get poorer performance on timed
  WAIS tasks

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Specific Tests (cont.)

• Imaging can be of limited benefit, as lesions are
  often found in brains of nondemented depressed
  elderly (periventricular more common in dementia)
• Possible small L hippocampus
• Probably medial temporal lobe atrophy

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Specific Tests (cont.)

• Some specialized measures have been developed,
  e.g. for specific characteristics of depression
  found in dementia
• E.g. Strauss, M. Sperry, S. (2002). An
  informant-based assessment of apathy in Alzheimer
  disease. Neuropsychiatry, Neuropsychology,
  Behavioral Neurology, 15(3), pp. 176-183

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Further Reading

• desRosiers, Gabriel. (2000). Depressive
  pseudodementia. In Berrios, German E. Hodges,
  John R. (Ed), Memory disorders in psychiatric
  practice. pp. 268-290. New York Cambridge.