Ruminative thinking in older inpatients with major depression

Abstract

Ruminative thinking, the tendency to dwell on particular ideas or themes, can be a prominent part of the phenomenology of major depression, but it rarely has been the focus of empirical research. We attempted to replicate (in adult psychiatric inpatients age ≥50 years with DSM-III-R major depression) the previously published finding that ruminative thinking was associated with melancholia and with psychosis. In our sample, these associations were not present. In addition, we explored the relationships of ruminative thinking to specific areas of thought content (e.g., suicidal ideation, somatic worry), cognitive function and overall functional status; ruminative thinking was not associated with suicidal ideation, but was associated with greater somatic worry and with poorer functional status, although these associations were not independent of overall depressive severity. A substantial proportion of subjects were unable to complete the cognitive measures; ruminative thinking was independently associated with inability to complete these tasks. We conclude that ruminative thinking is a meaningful and common clinical phenomenon among severely depressed older inpatients. Further investigations in inpatients and other populations examining its relationships to other phenomenology, to course and outcome, and to putative underlying mechanisms of depression are warranted.

Introduction

Empirical research regarding the phenomenology of major depression both contributed to, and was stimulated by, DSM-III and its descendants. On balance the recent DSMs have fostered consideration of clinical psychopathology, but a `side effect' of their criteria-specific diagnostic view has been the tendency to disregard clinical phenomena not mentioned in them. Ruminative thinking in depression is an example of this investigative neglect. As reviewed by Nelson and Mazure (1985), ruminative thinking was defined as `the tendency of the patient to dwell on one idea to the exclusion of other thoughts.' Severity of ruminative thinking exists along a spectrum, from mild self-reported preoccupations to fixations on the ruminative idea that totally dominate one's thoughts and conversations. Descriptions of ruminative thinking in melancholia date back many centuries (Jackson, 1986), but to our knowledge only one research group in the modern era has studied it empirically. Nelson and Mazure (1985), using a sample of psychiatric inpatients with DSM-III major depression, found that ruminative thinking was associated with the melancholic subtype of depression, consistent with their prior work demonstrating an association of ruminative thinking with depressive autonomousness (Nelson et al., 1981) and with delusional depression (Charney and Nelson, 1981). An association of ruminative thinking with melancholia might prove useful clinically, since melancholia itself may predict a different response to somatic and non-somatic therapies as compared with non-melancholic depression (Rush and Weissenburger, 1994). Yet no published studies since 1985 address this issue.

Given this background, we attempted to replicate the work of Nelson, Mazure et al. by testing the hypothesis that ruminative thinking in older patients is associated with melancholia and with psychosis. In addition we planned analyses to explore the relationships of ruminative thinking to other clinical realms, hypothesizing that ruminative thinking would be associated with greater suicidal ideation and somatic worry, and greater cognitive and overall functional disability.