Can J Psychiatry. 2011;56(7):385-386.
The numbers and proportions of elderly people are increasing in most countries in the world, and the number of people aged 65 years and older will increase, worldwide, roughly from 500 million to 1.5 billion between 2005 and 2050." The steepest rise will be in the group aged 80 years and older, which will increase roughly from 90 million to 400 million during the same period.' Mental disorders are common in the elderly, and they are among the most important factors for disability and low life satisfaction. The frequency of dementia increases steeply with increasing age, with a prevalence of 1% to 2% for people aged 70 years, 30% for those aged 85 years, and more than 50% for those aged 95 years.2-4 The number of people with dementia will thus increase dramatically during the next decades, especially in the developing world. Other mental disorders are also common, and depression is more common than dementia in people aged 65 years and older. However, these other mental disorders in the elderly have received much less attention than dementia from researchers and the general public. In addition, psychiatric symptoms are even more common in people with dementia, where it is related to worse function and suffering, both for the patients and their caregivers. In this issue of The Canadian Journal of Psychiatry, the 2 In Review articles are concerned with psychiatric disorders in the elderly. One discusses psychiatric disorders in the elderly without dementia,5 and one discusses psychiatric symptoms in people with dementia.6
Psychiatric disorders in the elderly constitute a special challenge for psychiatrists. There is evidence that the clinical expression, the pattern, and influence of risk factors, and the consequences of mental disorders may change with age. In addition, these factors also differ between elderly people with and without dementia. The influence of organic brain changes, cerebrovascular and other somatic diseases, cognitive function, and comorbidity may be especially relevant among the elderly. Finally, survival into old age increases, worldwide. This will result in more people with psychiatric disorders surviving with their disorder into old age. Little research has been done on how aging shapes the clinical expression of psychiatric diseases. For example, it is often suggested that manic episodes become less common with age in patients with bipolar disorders, or that panic attacks disappear in those with panic disorders.
Another special aspect in the management of elderly people with psychiatric disorders is related to pharmacological treatment. First, the elderly are more at risk for adverse side effects owing to slower metabolism and other age-related pharmacokinetic and pharmacodynamic changes. Thus they may not tolerate doses that are commonly used in younger patients. Conversely, interindividual differences increases with age, and many elderly people are treated with toolow doses owing to the concern for side effects. Second, multipharmacology is common in the elderly, which may lead to dangerous interactions. Third, side effects not reported in younger age groups may appear in the elderly and people with dementia. One example is the increased risk for stroke and premature death related to neuroleptic drug use in people with dementia. Fourth, the elderly have more comorbid somatic conditions, which may affect treatment. Despite all these factors, trials are seldom executed in the elderly, and results from trials in younger age groups may not be relevant in trials of the elderly. Further, exclusion criteria normally used in drug trials may result in the selection of patient groups that are not representative of elderly patients. Finally, all doctors concerned with the elderly, including psychiatrists, need to evaluate cognitive function in their elderly patients, as it may have implications for drug adherence. Impaired cognitive function does not necessarily point to a diagnosis of dementia, as most psychiatric disorders in the elderly give rise to cognitive symptoms. …