"Depression is perhaps the most frequent cause of emotional suffering in later life", Dan. G. Blazer, "Depression in Late Life: Review and Commentary"¹.

In our ageing society, where longer life is not necessarily the same as longer healthy life, the problem of elderly depression can reach farther than the undoubted emotional suffering of elderly individuals.

It is also characteristic of the fabric of today's society in which families disperse and are leaving the elderly isolated, especially those who survive the death of their partners.

Elderly depression can be described as medically 'interactive': if I have been ill for some time, my illness can be the cause of my depression"; that's logical. It applies also in reverse: I am clinically depressed, then I may become more vulnerable to other diseases of ageing. Co-morbidity with depression is a profound and growing problem in old age.

The combination of medical and social aspects of elderly depression is also putting increasing economic pressure on society's financial burden in trying to provide satisfactory health care and long-term care.

Clinically, elderly depression is no longer a total mystery, but its causes and consequences remain complex. In recent years, research has materially advanced our state of knowledge, and we certainly have a far better grasp of treatment than we had a generation ago. Yet elderly depression is on a rising tide against which society's defences are relatively weak, because our knowledge is not being applied consistently in the practice of medical and long-term care. Too often elderly depression remains undiagnosed, denied by patients, untreated or overdosed, and complicated by co-morbidity. Too often, patients' adherence to prescribed treatment is allowed to lapse.

In short, the core challenge of elderly depression in our time is not primarily one of understanding the condition but rather one of managing it effectively.

Prevalence

Reports differ widely, because the studies on which they are based range from examining depression to milder forms of depressive symptoms. Observation of age groups, too, can vary from 55+ or, commonly 65+ to the 'oldest old'. Interview techniques to determine the presence and level of depression vary. Perhaps of greatest significance are differences in prevalence between elderly persons living in the community and residents of institutions.

The following tables give a snapshot of a range of findings in recent years.

Although many studies of depression in persons of all ages have indicated that the condition is less prevalent among the elderly than among the young, the above examples imply that major depression probably increases appreciably with advancing age between 55 and 'the oldest old'. There are indeed indications that the rate of increase of major depression may be causally related to the rise in the elderly component of the population. At the very least, it would be prudent to regard the possibility of such a relationship as a warning signal for health authorities in ageing societies.

The figures for 'other depression' are less firmly defined than those for major depression, but they suggest an interactive relationship between elderly depression and other forms of chronic disease, as well as showing a striking increase between community dwelling and residence in nursing homes. They do not, however, reveal the extent to which nursing home depression is simply a consequence of severe chronic disease as distinct from the psychiatric and physical impact of the atmosphere and management of nursing homes.

Cause and effect in elderly depression - room for exploration

Although our clinical and psychiatric awareness of cause and effect in elderly depression is extensive, many of the social and cultural levers remain contradictory or unclear. For example, the gender gap. Virtually all studies of elderly depression in Europe and North America have observed that its prevalence among women is far higher than among men (1.65:1 in the analysis of nine European centres in the table, above). But a study of 2,633 adults in Chinese cities has concluded that the gender difference is insignificant, except in the 35-49 age group where the lifetime prevalence of major depression for men was 3.6% compared with only 2.3% for women³. Even in the West, the gender gap is perhaps less conclusive than appears at first sight, because there are also indications that men are more reluctant than women to acknowledge that they are depressed, and less willing to seek professional diagnosis and treatment. If women go to the doctor or the psychiatrist while men go into hiding, it is unwise to take gender gap statistics at face value.

There is a cultural dimension to elderly depression that defies simplistic analysis of comparative statistics. How else can we explain the fact that the meta-analysis of nine European centres (Ref.2) reported wide geographical divergence in the prevalence of elderly depression? The reported range is from Iceland (8.8% at age 88-89) to Munich (23.6% at 85+). Among other centres that measured depression in the 65+ age group, Zaragoza reported 10.7%, Liverpool 10.9%, Berlin 16.5%, London 17.6% and Verona 18.3%.

The divergence in 'depressive symptoms' (as distinct from clinical depression) between European centres was even more pronounced among the 'oldest old'. For example in men aged 85+, 2% declared 'life not worth living' and 3% 'wish to be dead' in Iceland compared with 16%/25% respectively in Berlin and 30%/29% in Munich.

The authors of the European meta-analysis concluded that "considerable variation existed in the levels of depression across Europe, although the cause was not immediately obvious" but they thought that the extreme level of depressive symptoms in the 85+ group in German cities "may have been due to the lingering aftermath of the Second World War in this generation" (Ref.2).

The complexity of elderly depression has been described in terms of 'vulnerabilities to relapse, recurrence and chronicity' by W. J. Apfeldorf and G. S. Alexopoulos⁴. Contributory factors are listed as:
• Advanced age
• female gender
• medical burden
• severity of depression
• cognitive dysfunction
• multiple personal loss/bereavement
• chronic insomnia
• limited access to treatment
• cerebrovascular, Alzheimer's, Parkinson's Disease
• depletion of psychosocial resources

Several items on this list are distinctive and characteristic for elderly persons. The differences between depression in elderly and younger persons will be explored in the second article of this series.
 

Footnotes
[1]  J. Gerontology: Medical Sciences 58A, No.3, 249-265, 2003
[2]  R.M. Copeland et al, "Depression among older people in Europe: the EURODEP studies", World Psychiatry, 3[1], 45-49, February 2004
[3]  S. Lee, A. Tsang et al, "The epidemiology of depression in metropolitan China", Psychological Medicine 39, 735-747, May 2009
[4]  "Approaches to the Treatment of Chronic Late-Life Depression", Handbook of Chronic Depression, eds. J. E. Alpert & M. Fava, , p.317-337, Marcel Dekker Inc, New York &Basel 2004

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