An aetiological model of non-melancholic depression: study design and validity of the measures.

Abstract

The aim of this paper is to describe an approach to sub-typing non-melancholic depression and to determine which raters from a variety of backgrounds provided the most valid information on study variables. A sample of non-melancholic depressed patients is described. Multiple raters (i.e. patients, psychiatrists, referrers and corroborative witnesses) completed measures of the patient's trait anxiety levels, severity of recent life event stressors and personality functioning. The study and representative data are reported. Congruence between several measures employed indicated that psychiatrist rating of disordered personality was superior to corroborative witness report. Assessment of anxiety traits indicated reasonable agreement between referrers and corroborative witnesses but poor agreement between those ratings and interview-elicited ratings. There were also discrepancies in quantifying 'severity' of life event stress, with patients and their corroborative witnesses rating such events as more severe than either the interviewing psychiatrist or psychiatrists involved in consensus rating sessions. Importantly, the psychiatrists' capacity to quantify the relative contribution of disordered personality, anxiety and life-event stress to the particular depressive episode was supported. Results indicate some of the difficulties in operationalising determinants that may contribute to and sub-type the non-melancholic depressions, and demonstrate the advantages of using a range of rating strategies and raters. In this study, psychiatrist-generated judgements are clearly favoured, although the advantages of also assessing trait anxiety and life-event stress impact by self-report strategies are conceded. Some techniques for estimating the contribution of disordered personality function, anxiety and life-event stress are offered for both their research and their clinical utility.