IPDE - Extranet Systems - World Health Organization

83 Discussion and Conclusions
Repetitions can lead to boredom and decreased motivation. Patients may
also believe that the interviews are no longer for their benefit but for that
of the examiner. Repetitions can also produce fantasies that the interviewer
is dissatisfied with the previous interview or is checking on the
consistency of the responses. Patients may also refrain from providing as
many positive replies as previously because of a heightened awareness
that these invite further probing and prolong the interview. Elsewhere,12
I have argued that the problem of attempting to measure the precise
degree to which interviewers are interchangeable is reminiscent of the
Heisenberg principle in physics: one cannot measure the phenomenon
without somehow tampering with it in the process.
Another source of temporal instability is the possibility that patients
in a dysphoric state may have a selective recall or distorted perception of
certain personality traits. They may also confuse them with the symptoms
of another (Axis I) mental disorder. An earlier version of the PDE
proved resistant to changes in symptoms of anxiety and depression
during the course of treatment? In that study, the majority of patients
had mood or anxiety disorders of mild to moderate severity. The finding
has since been replicated with the DSM-III-R component of the IPDE
(Loranger & Lenzenweger, 1992 unpublished). There is, however, a
contradictory report based on a group of depressed patients treated
with cognitive therapy.13 That study used an earlier version of the PDE
and the authors failed to specify the professional status and training
of the interviewers, a potentially relevant variable. It may require an
experienced psychiatrist or clinical psychologist to distinguish personality
traits from transient pathological mental states and the symptoms
of other disorders. The reliability and validity of the IPDE, like that of
any semistructured inteniew, cannot he judged apart from the qualifications
of the interviewers. At times, semistructured interviews have
assumed a mystique of their own. and that caveat all too often ignored.
The IPDE is intended for use by those who have the clinical sophistication
and training required to make psychiatric diagnoses independently,
i.e., without a semistructured interview. This is not to imply that the
IPDE or any other PD interview is necessarily impervious to the influence
of abnormal mental states, particularly those characterized by
severe symptoms. We are encouraged. however, by the evidence that
some clinical states do not appear to invalidate the assessment of personality.
In any event, no attempt was made to determine the extent to which
trait-state artifacts may have affected the stability of the IPDE in the
present study.