The natural history of depression and the anxiety disorders in older people:

Abstract

Background: This study reports the outcome of depression and anxiety disorders in older people. Methods: Follow-up of 165 subjects age 65 or over, initially identified in a community study in inner London as depressed or having an anxiety disorder. Results: 117 subjects still living in the area; 25 had died. Death was predicted only by activity limitation at first interview and not by other demographic or morbidity variables. Eighty-six subjects reinterviewed; 21 males, 65 females. Of the depressed, 34% had recovered, 39% were depressed and 27% were dead. Predictors from initial interview of continuing depression were female gender and more severe depression. Of those with phobic anxiety, 16% had recovered, 18% died and 66% were still phobic. Predictors of continuing phobic anxiety from initial interview were female gender and “stand-alone” phobic anxiety, i.e., not being depressed at initial interview. Sixty percent of those with early onset phobias had specific phobias; 82% of those with late-onset phobias had agoraphobia. Twenty-two subjects were prescribed psychotropics. The only significant predictor of psychotropic prescription was having sleep disturbance at initial interview. A low score on life satisfaction was significantly correlated with depression but not with phobic disorder. A high score was correlated with not having a current psychiatric disorder. Limitations: Some subjects were lost to follow-up. Those on psychotropics were particularly likely to refuse an interview. Conclusion and clinical relevance: In older people, neither depression nor the anxiety disorders generally remit spontaneously. Those with a particularly poor prognosis are women and those with a more severe depression. Agoraphobia may be precipitated in older people by stressful events and interferes with life satisfaction. There is potential for increased pharmacological treatment of older people with affective disorders.

Introduction

Depression is the most prevalent psychiatric illness in old age (Livingston and Hinchliffe, 1993) and is often amenable to treatment (Burvill, 1993). There have however been only limited studies of its outcome in the community. The four published studies (summarised in Table 1) took place in different countries (South Africa, UK, Singapore and Australia respectively) and find prevalences of depression at baseline ranging from 3% to 15%. Only one study is able to report on the outcome of more than a small number of subjects (Green et al., 1994). Despite this there is remarkable similarity in the proportion who recovered from depression, around 50% of each follow-up cohort. The outcomes in terms of mortality and remaining depressed were however much more varied.

Bowling et al. (1996)followed up older subjects 2.5 to 3 years after they were initially classified as psychiatric cases according to the General Health Questionnaire (Goldberg and Williams, 1988). Formal diagnoses were not made in this study. Thirty-one (47%) of those re-interviewed had recovered. Those who remained ill were likely to have poorer functional ability. Marital status, age and sex was not associated with outcome.

The anxiety disorders were thought to be uncommon in older people (Henderson and Kay, 1984) and are infrequently diagnosed in primary care after age 40 (Lindesay, 1991). The anxiety disorders are less common in older than younger adults (Flint, 1994), despite reports that agoraphobia often begins after the age of 65 and is then frequently attributed to an episode of physical illness or a traumatic event (Lindesay, 1997). Recent community surveys have, however, found that anxiety disorders have a prevalence rate of about 15% in older people, which is similar to the rates of depression found in the same cohorts (Lindesay et al., 1989, Manela et al., 1996). In the latter study while generalised anxiety was usually comorbid with depression, phobic anxiety was not (see Fig. 1).

There are no published reports on the natural history of untreated anxiety (including phobic) disorders in any adult age group. In a 5 year follow-up of patients of all age groups seen in secondary services with primary major depression and phobias, it was found that 94% recovered from the index episode but 52.5% were hospitalised at 5 year follow-up, and 73% were on antidepressant treatment (Coryell et al., 1992).

The present study aimed to report on the natural history and outcome of depression and the anxiety disorders in a community sample of older people; to assess impact on life satisfaction and to identify factors associated with recovery and continuing morbidity.