Discuss issues of reliability and validity associated with the classification and diagnosis of phobic disorders (8 + 16 marks)
A phobia is a persistent fear that is excessive or unreasonable which must meet a set of criteria given in the DSM. A clinical diagnosis is made if there is no other possible physiological cause and if the symptoms cannot be better accounted for by another disorder. The individual also recognises their behaviour is unreasonable and the severity of the fear interferes with an individual’s normal functioning.
Conducting research on the effectiveness of treatments for phobic disorders require researchers to have a reliable and valid means of assessing disorders. Reliability is the consistency of a measuring instrument, 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. Hiller et al. (1990) reported satisfactory to excellent diagnostic agreement in a test-retest study using the Munic Diagnostic Checklist which is structured and self-administered. This high reliability may be due to the fact it’s self-administered, as there is less opportunity for the administrator to affect the responses that are given. Also, people with social phobias might prefer this due to their fears of negative evaluation. Another way of assessing reliability is whether two independent assessors give similar scores, which is called inter-rater reliability. Skyre et al. (1991) assessed inter-rater reliability for diagnosing social phobias by asking three clinicians to assess 54 patient interviews obtained using the SCID, a semi-structured interview requiring extensive training to administer which could explain the high reliability. High inter-rater agreement of +72 showed the diagnosis of phobia is reliable. However, Kendler et al. (1999) found contrasting results using face-to-face and...
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