Abnormal Psychology - Validity and Reliability Flashcards
What is abnormal psychology
The studies of psychological disorders
Diagnosis and Abnormal Psychology
- Difficult to define abnormal behaviour -> therefore it is difficult to diagnose (based on the symptoms people exhibit or report)
- Making a correct diagnosis is extremely important because this determines the treatment people receive.
How are diagnoses carried out
- using a standardised system (diagnostic manual)
- clinicians rely on self reported data, physiological testing, clinical observation etc
Affective symptoms (emotional elements)
Behavioural symptoms
Cognitive symptoms (ways of thinking)
Somatic symptoms (physical symptoms)
limitations on diagnoses
- Has no clear definition of normality or abnormality
- symptoms vary between individuals and social and cultural groups
- diagnoses an be biased or wrong
- definitions of abnormality/normality can change over time
- HOWEVER can use data triangulation to increase validity of data (obtains data from two or more sources)
what is a classification system
they identify patterns of behavioural or mental symptoms that consistently occur together to form a disorder
EX: DSM-5 (standardised system for diagnosis) [mainly in USA] and ICD (International Classifications of Diseases)
issue with classification systems
- difference between classification systems
- updated and change over time
- level of reliability
What is validity of a diagnosis
Whether a diagnosis is correct and leads to successful treatment
What is reliability of a diagnosis
Whether two or more psychiatrists using the same classification system make the same diagnosis
Many symptoms are difficult to measure. (feelings of helplessness, or hearing voices)
Psychiatrists are heavily dependent on self-reported data and this is known to result in some bias.
Individuals may suffer from two or more psychological disorders simultaneously. This is known as comorbidity
Lobbestael, Leurgans & Arntz (2011)
Aim : To investigate the reliability of diagnosis using the DSM IV
Sample: 151 (Patients and non-patients)
Method: Single blind procedure
Procedure:
1. Original clinical interview (~2 hr) were audiotaped
2. Interviews were assessed by a second psychiatrist who didn’t know initial diagnosis
Results:
- Generally higher reliability for personality disorders compared to other disorders
- high rate of consistency
- doesn’t mean results are reliable
Conclusion
- High consistency in diagnosis, suggesting DSM IV aids agreement among clinicians.
Evaluation of Lobbestael, Leurgans & Arntz (2011)
Strengths:
- Single blind
- using audiotapes : non-verbal behaviour/appearance of patient did not affect diagnosis process
Limitations:
- using audiotapes : difficult to know which non-verbal behaviour may have played a role in the first diagnosis
- the second diagnosis may be too controlled and could have missed important non-verbal data which may have changed the diagnosis.
