Characteristics of depression in neurologically impaired and normal elderly.

Abstract

Severity and pattern of depressive symptomatology were examined among four groups of elderly individuals, i.e., patients with DSM-III diagnoses of major depression (n = 54), patients with presumed dementia of the Alzheimer's type (DAT) (n = 27), patients with idiopathic Parkinson's disease (PD) (n = 30), and normal controls (n = 29). The depressed elderly group obtained significantly (p < .001) higher means, and the control group obtained significantly (p < .01) lower means, than the neurologically impaired groups on clinician ratings (Hamilton Rating Scale for Depression, HRS-D) and self-report (Beck Depression Inventory, BDI) of depression. However, HRS-D means of the PD and DAT groups did not differ significantly (p < .125). The depressed elderly group also obtained significantly (p < .001) higher means than the contrast groups on HRS-D vegetative and cognitive depression primary factors (adapted from Rhoades & Overall, 1983), while the control group obtained significantly (p < .001 to 0.01) lower means. At the intermediate level, the PD mean on the vegetative factor was significantly (p < .05) higher than the DAT mean, while the groups did not differ significantly (p < .79) on the cognitive factor. The depressed elderly group obtained a substantially lower interfactor correlation coefficient than the neurologically impaired groups, suggesting greater heterogeneity in manifestation of depression at moderate than at mild levels of severity. However, the finding of zero variance on some HRS-D items for the neurologically impaired groups suggested that factor structures may differ for PD, DAT, and depressed groups. For PD patients, the prediction that PD symptom severity ratings would correlate more highly with clinician ratings (HRS-D) than self-report (BDI) of depression, due to PD symptoms that resemble depression, was not supported. Speculation that the DAT group might report less depression due to loss of insight was not supported in this group of mildly to moderately demented patients. Only 22% demonstrated loss of insight, while 93% exhibited some degree of depressed mood on the HRS-D. Over 50% of the control group of PD spouses and community volunteers endorsed some degree of fatigue, work inhibition, and decreased libido, illustrating the need for considering base-rates in assessment.