Clinical and Methodological Factors Related to Reliability of the Best-Estimate Diagnostic Procedure

Abstract

These results suggest that it is possible to identify cases that are more likely to lead to diagnostic disagreements in family and epidemiological studies and that blind diagnoses may help to prevent false positive diagnoses, which may be particularly detrimental to genetic linkage analyses.

Shared and specific susceptibility loci for schizophrenia and bipolar disorder: a dense genome scan in Eastern Quebec families

“…We indeed reported data showing that, in case of disagreements between diagnosticians, unblind bestestimate diagnoses tended to be in continuity with the most predominant diagnosis of the pedigree more frequently than blind diagnoses. 26,31 However, other studies using similar methods did not find high rates of mixed pedigrees. One cannot eliminate the possibility that the observation of such mixed pedigrees be a particularity of the Eastern Quebec population.…”

“…The ascertainment, diagnostic methods and reliability have been described in detail in previous reports. 15,26,31,36 Briefly, information from an interview with the subjects (Structured Clinical Interview for DSM-III-R), from relatives and from the lifetime medical records, was gathered. Based on this information, a consensus best-estimate DSM-III-R diagnosis (BED) was derived by a panel of four research psychiatrists who were blind to diagnoses in relatives.…”

“…26,27 This decision was motivated (i) by family studies suggesting some degree of familial coaggregation of SZ and BP 4,[28][29][30] and (ii) the need to preserve total blindness to the predominant diagnosis in an SZ or a BP pedigree to avoid a diagnostic bias that we showed as significantly affecting diagnostic accuracy. 31 Two other sets of findings support this SZ/BP commonality. First, we were among the first to demonstrate, by means of factor analysis, that the dimensional model of Liddle crossed diagnostic boundaries and was common to SZ and BP, 27 which has been confirmed in other populations.…”

A search for specific and common susceptibility loci for schizophrenia and bipolar disorder: a linkage study in 13 target chromosomes

“…17,18 Briefly, information from an interview with the subjects (using the Structured Clinical Interview for DSM-III-R), from relatives and medical records, was gathered. Based on this information, a first best-estimate DSM-III-R diagnosis (BED) was derived by the field team, unblind to diagnoses in relatives.…”

Génétique de la schizophrénie et de la maladie bipolaire

“…Ces derniers ont compris qu'un niveau majeur de complexité pour la SZ et la BP réside dans l'incertitude de la définition du phénotype tel qu'utilisé dans les études de liaison et les études d'association précédentes. Un pré-requis crucial, cependant, est que la méthodologie strictement à l'insu [10,11] soit maintenue tant par les cliniciens qui échantillonnent les généalogies et le phé-notype diagnostique que par les laboratoires qui produisent les génotypes. Ce ne fut pas toujours le cas dans les études pionnières.…”