Discuss issues of reliability and validity associated

Discuss issues of reliability and validity associated with the classification and diagnosis of phobic disorders. ( 8+16) A phobia Is an irrational fear which Interferes with daily life. For a phobia to be diagnosed It must meet the criterion set by the diagnostic and statistical manual of mental disorders. Reliability and validity are two Important factors when considering classification of mental disorders; they must be present for an accurate classification to be made. Rellablllty and valldlty are linked because a diagnosis that Is not reliable Is not valid.Rellablllty refers to the consistency, such as questionnaires or scales to assess how fearful a person Is about something. Reliability of questionnaires or scales can be measured In terms of whether the test items are consistent, which Is called test-retest reliability. Another way of assessing reliability is whether two independent assessors give similar scores, which is called interrater reliability. Test re-test refers to how consistent results are when the specific interview/questionnaire is repeated.Brown et al (2001) conducted study which involved interviewing 1400 patients twice, the second interview occurred within 2 weeks of the first one. The interviews were based on criteria for various disorders in DSM -IV. Brown found that reliability in inter-rater agreement was excellent for specific phobia, social phobia and panic disorder wit agoraphobia. Reliability could have been higher for the various phobias than for other mental disorders because all phobias are associated with clear behavioural symptoms (avoidance of feared stimulus) which makes them easy to diagnose.This suggests hat diagnosis of phobic disorders according to the DSM is reliable however largely because phobic disorders are easy to diagnose . Brown et al also examined factors associated with disagreement between 2 interviewers. He found that inter-rater unreliability was caused by interviewers disagreeing whether the fear was causin g sufficient distress/interference to a person's life to warrant a phobia diagnosis. It was also caused by patient's reports of symptoms changing between interviews which could have been genuine.Another cause of difference between the two interviewers as that they made errors, as the same symptoms were presented to interviewers however different diagnosis given however this could be because they missed Important information. Skyre et al (1991) also found high Inter-rater reliability, 3 cllnlclans assessed 54 patients using SCID-I. He found +72 Inter-rater agreement which shows that phobia diagnosis Is reliable. Diagnosis of phobic disorders ld also reliable as Hiller et al (1990) found satisfactory – excellent diagnostic agreement In a test- retest study using MDC.Valldlty Is the extent to which a classification system easures what It claims to measure. We can assess the valldlty associated with phobic disorders by looking at content valldlty. Content validity means how much the diagnostic system addresses all of the symptoms In a given disorder. Seml structured interviews have high content validity because they were made to the classification system is vaild is to look at criterion validity. This looks into if individual receiving a diagnosis e. g. social phobia are any different to the people who have not been given the diagnosis in predictable way .