Importance of diagnosis
- Provides info on possible causes of symptoms and direction of treatment.
- Enables clinicians and scientists to communication accurately with one another.
- Research on causes and treatments of symptoms
- Reliability refers to the consistency of measurement.
- Interrater reliability: refers to the degree to which two independent observers agree on what they have observed.
- In psychology, interrater reliability refers to the extent two clinicians observing the behaviour of the same patients agree on a diagnosis.
- Test-retest reliability: measures the extent to which people being observed twice or taking the same test twice receive similar scores.
- Internal consistency reliability: assesses whether the items on a test are related to one another. For example, one would expect the items on an anxiety questionnaire to be interrelated or to correlate with one another, if they truly measure anxiety.
- Reliability is typically measured on a scale from 0 to 1.0; the closer the number is to 1.0, the higher the reliability
- Validity: whether a measure measures what it is supposed to measure.
- Content validity: refers to whether a measure adequately samples the domain of interest.
- Criterion validity: whether a measure is associated in an expected way with some other measure (the criterion).
- Predictive validity: evaluating the ability of the measure to predict some other variable that is measured at some point in the future (type of criterion validity)
- Construct validity:the degree to which a test measures what it claims, or purports, to be measuring
The diagnostic and statistical manual of mental disorders (DSM)
- Changes: characteristics are described more extensively
- Removal of multiaxial
- Enhanced sensitivity to the developmental nature of psychopathology
- New diagnoses
- Combining diagnoses
Specific criticisms of the DSM
- Too many diagnoses?
- Some argue that this overlap (comorbidity) is a sign that we are dividing syndromes too finely.
- Categorical classification versus dimensional classification. A categorical system forces clinicians to define one threshold as ‘diagnosable’.
- Even when following criteria, there is some room for disagreement in DSM-5.
general criticisms of diagnosing psychological disorders
- Stigmatising effect
- When a diagnostic category is applied, may lose sight of the uniqueness of person.
Diagnosis vs case conceptualisation
- Case conceptualisation: case conceptualisation is a way of collaboratively working with patients to personalise service.
- A way of making sense of a patient’s difficulties in the context of a theoretical framework.
- Popular approach: 5 P's
- 1. Presenting problem
- 2. Predisposing factors: any possible contributors to the problem
- 3. Precipitating factors: significant events preceding onset
- 4. Perpetuating factors: any current difficulties that are maintaining the presenting problem
Case conceptualisation has been criticised for having low interrater reliability
. However, interrater reliability can be improved with training in case conceptualisation practices and clinical experience
- Used to help make diagnosis
- Used to identify appropriate therapeutic interventions
- Used to monitor the effects of treatment over time.
- Fundamental to conducting research on the causes of disorder.
- Use both formal and structured, as well as more informal and less structured.
- Interviewer pays attention to how the respondent answers or does not answer quesitons.
Assessment of stress
Stress can be conceptualised as the subjective experience of distress in response to perceived environmental problems.
Cautionary note about neurobiological assessment
- Many of the measurements do not differentiate among emotional states.
- Being in a scanner is often a threatening experience.
- Brain-imaging techniques do not allow us to manipulate brain activity and then measure change in behaviour.
- In attempting to understand the consequences of any brain dysfunction, one must understand the pre-existing abilities that the person had prior to diagnosis with a psychological disorder.
Cultural bias in assessment
Refers to the notion that a measure developed for one culture or ethnic group may not be equally reliable and valid with a different cultural or ethnic group.
Strategies for avoiding cultural bias in assessment
- Graduate training programs
- 1. must learn about basic issues in assessment, such as reliability and validity.
- 2. students must become informed about the specific ways in which culture or ethnicity may impact assessment rather than rely on more global stereotypes about a particular cultural or ethnic group.
- 3. students must consider that culture or ethnicity may not impact assessment in every individual case
clinicians are encouraged to be particularly tentative about drawing conclusions regarding people from different cultural and ethnic backgrounds. Rather, they are advised to make hypotheses about the influence of culture on a particular person, entertain alternative hypotheses and then test those hypotheses