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PSYCHIATRIC EPIDEMIOLOGY

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Case Register Studies. Any Epidemiological study can be Observational or Experimental ... New Haven: Hollingshead and Redlich (1950) ... – PowerPoint PPT presentation

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Title: PSYCHIATRIC EPIDEMIOLOGY


1
PSYCHIATRIC EPIDEMIOLOGY
2
Definition
  • Study of the distribution of illness in
    populations over time and space
  • The study of Mass aspects of disease
  • The pursuit of recurrent and predictable patterns
    of behaviour in a given population

3
Uses of Epidemiology
  • Completing the clinical picture
  • Community Diagnosis
  • Secular changes in incidence
  • Identification of Risk Factors/Protective
    Factors/Prevention
  • Delineation of syndromes
  • Planning services

4
Epidemiology Terms
  • Rates and Ratios
  • Prevalence
  • Point
  • Period
  • Lifetime
  • Treated and untreated
  • Inception (Incidence)

5
Prevalence and Inception Rates
  • Persons
  • A -----------------------
  • B ---------------
  • C ------------
  • D
    ------
  • E
  • ____________________________
  • t0 t1
    t2 t3

6
Base Population
  • General population or population subgroup
  • Primary care population
  • Mental health service population
  • Psychiatric Case Registers

7
Epidemiological Research Design
  • Cross-Sectional Studies
  • Longitudinal Studies
  • Prospective
  • Retrospective
  • Case-Control Studies
  • Case Register Studies
  • Any Epidemiological study can be Observational or
    Experimental

8
Design of a Community Survey
  • Defining the base population (sample frame)
  • Sampling method
  • Case Identification/definition (ascertainment)
  • Survey Instruments
  • Contact and Consent
  • Interview
  • Data entry and analysis

9
The Problem of Psychiatric Case Definition
  • Informal clinical judgement (Essen Moller,
    Hagnell,1966)
  • Categorical and dimensional approaches (Srole et
    al, 1962)
  • Reliability and Validity
  • Computerized Diagnosis

10
Sampling
  • Individuals, households, addresses,postcodes
  • Random sampling
  • Stratified sampling
  • Comparison with base population characteristics
  • Sampling error, failure of the base population,
    non cooperation, and distorted data from
    respondents

11
Instruments
  • Questionnaires
  • GHQ
  • HAD
  • Becks inventories
  • Symptom checklists
  • Rating scales
  • Hamilton Depression Scale
  • Bech Raphaelson Mania Rating Scale
  • MIMS?

12
Establishing a causal link between event and
disorder
  • Case
  • Yes
    No
  • Yes a b
  • Exposed
  • No c d

13
Instruments
  • Interviews
  • Structured (same questions asked of all subjects)
  • Semi-structured ( same topics covered with some
    leeway for follow on questions
  • Unstructured ( interviewer use their own clinical
    judgement)

14
Structured Interviews
  • Can be applied by trained lay persons
  • Statements and wording pre-set
  • Standard
  • Examples
  • DIS
  • CIDI

15
Semi-Structured interviews
  • PSE
  • SCAN
  • CIS

16
Issues of Reliability and Validity
  • Reliability
  • Interrater agreement
  • Test-retest
  • Validity
  • Construct
  • Content
  • Correlation with gold standard

17
Sensitivity and Specificity
  • Cases by full
    psychiatric

  • assessment
  • Yes
    No
  • Cases by screening Yes a(TP) b(FP)
  • Test
  • No c(FN)
    d(TN)

18
Chicago Study Faris and Dunham (1922-1934)
  • 35,000 admissions to mental hospitals
  • 1st admissions for schizophrenia highest in inner
    city areas within lowest socioeconomic groups
  • Led to the social drift and social segregation
    hypotheses
  • And to the social causation and social selection
    theories

19
Midtown Manhattan Rennie and Srole (1954)
  • 1660 adults, structured interview by non
    psychiatrists
  • Incidence of mental disorder increased with age
  • Low socioeconomic group had 6 times as many
    symptoms as those in the high groups

20
New Haven Hollingshead and Redlich (1950)
  • Social class and prevalence of treated mental
    disorder
  • Census of psychiatric patients, community survey,
    survey of psychiatrists and controlled case study
  • Described 5 distinct social classes and found
    neurosis in high classes, and psychosis more
    prevalent in lower classes
  • 15.1 of population above 26 showed evidence of
    mental disorder

21
Stirling County Alexander Leighton
  • 20,000 rural persons ,non-clinicians, structured
    interview, later psychiatrist rating
  • 24 had notable impairment, and 20 needed
    psychiatric attention
  • Womengtmen, morbidity increases with age and
    poverty

22
NIMH-ECA Survey Regier et al 1998-
  • 20,000 from various sites across the US
  • Structured interview, DIS, lay interviewers
  • 15 one year prevalence of mental disorder in US
    population, 1/5 untreated, 1/5 treated by mental
    health, 3/5 primary care
  • Depression women 2/men1
  • Men more alcohol and substance misuse

23

24
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25
Psychiatric Morbidity in Upper Egypt (n5291)
26
The Future of Psychiatric Epidemiology
  • Molecular genetics and epidemiology
  • Risk factors and dimensional measures of
    psychopathology
  • Cross-national differences in the prevalence of
    disorder
  • Changes over time (secular) changes in the
    pattern and prevalence of disorders

27
  • Group I Design an epidemiological study to test
    the hypothesis there is higher prevalence of
    psychosis in prisons compared to the general
    population.
  • The design should include detecting associations
    with potential risk factors for any excess of
    psychotic disorders in persons serving a prison
    sentence

28
  • Design an epidemiological study that could
    determine the prevalence and demographic
    correlates of psychiatric disorder in the general
    population.

29
  • Design a study to examine the following null
    hypothesis The prevalence of psychiatric
    morbidity was the same in 1977 and 1985. How will
    you explain any changes in prevalence detected by
    the study

30
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