Depression in later life: What GPs need to know

Depression in later life

Given the multiple losses experienced by the older population, there is a presumption by society that depression is inevitable and an understandable part of the aging process. However, the clinical implication of failing to diagnose depression has significant consequences for the physical health, social interaction and overall quality of life of the individual.

Epidemiology

The literature lacks reliable estimates of prevalence rates in those over the age of 85 years and the rates reported are likely underestimated. Differentiating depressive symptoms from those of many physical health issues is challenging.

Symptoms and signs of later life

Commonly physical symptoms are features such as fatigue, weight loss, pain, poor oral intake and gastrointestinal upset. Moreover, they can typically experience a greater level of anxiety and rumination. An older population can also present with subjective memory loss and cognitive deficits.

Psychomotor changes can be seen in up to 30% of depressed elderly patients with psychomotor slowing or agitation. Indeed, social isolation, increasing alcohol use and self-neglect are also common features.

Psychosis is common in late onset depression. Clinical features commonly seen are persecutory delusions, auditory and visual hallucinations. First-rank symptoms, negative symptoms and thought disorders are uncommon. Importantly, delirium must always be considered which can result secondary to a medical condition or may be drug-induced.

Presentations of later-life depressions

Those in residential care and hospital inpatients have a significantly increased risk of depression compared to their community-dwelling peers. Other triggers which are important to look out for are bereavement, sleep deprivation, loss of income/productivity, change in social status and loss of physical and cognitive abilities.

Clinical course and complications

It is important to highlight that although society recognises the problem with rates of deliberate self-harm in the younger population, rates of completed suicide tend to rise with age. In fact, completed suicide rates are two-fold higher in later life than the general population and rates have unfortunately been persistently high over recent decades. Men have a higher rate of suicide in later life with ratio of 3:1 in most countries.  Risk factors for deliberate self-harm in the older population include physical illness, loneliness, widowhood and living alone.

When investigating clinical depression in the older adult, it is essential to include a cognitive assessment and blood work-up (glucose, thyroid function, vitamin B12 and folate levels). Depression is a risk factor for Alzheimer’s disease and vascular dementia. The prevalence of depression in those with Alzheimer’s disease is between 30-50%, especially in the initial stages of the condition.

Subtypes

As stated earlier cognitive impairment can be associated with depression in later life. Individuals with late onset depression can have attention and executive dysfunction whereas those with recurrent early onset depression may have deficits with memory. When depression is associated with concurrent cognitive deficits, it can be referred to as ‘pseudodementia’. This is transient cognitive impairment with depressive features. Organic causes for an underlying cognitive change must be excluded before the term ‘pseudodementia’ can be used. Some studies have demonstrated that those with pseudodementia are at higher risk for irreversible dementia in the future, with one study reporting an incidence rate of 40% with a three-year follow up (Alexopoulos, 2005), implying a less benign prognosis than previously thought.

Depression due to a medical condition has also been defined. With higher incidence of medical comorbidities in the older population, this term can be applied to many cases of depression. Depression can be a prodromal symptom of neurological illness especially many subtypes of dementia as previously mentioned. There is an abundance of research reporting higher incidence rates of depression in older adults in the presence of medical conditions in particular the 3 Cs; cardiovascular, cancer and central nervous system (stroke, dementia and Parkinson’s disease). The prevalence rate of depression among geriatric patients in a medical hospital is approximately 30%.

Vascular depression is another subtype of late onset depression that has been proposed. Individuals with small vessel disease resulting in ischaemic changes to the frontal subcortical areas is hypothesized to perpetuate depression in later life. Vascular dementia is described to have a collection of clinical features such as apathy, psychomotor retardation, poor executive function and less emotionally intense cognitions such as worthlessness compared to late onset depression without vascular risk factors.

Recovery and remission

If antidepressants are stopped soon after recovery, one in two patients will experience depressive symptoms within three to six months. Unfortunately, more than 50% of those who had one episode of major depression will have a second episode, and more than 80% of those who had two episodes may have three. NICE guidelines recommend that patients who’ve had two or more episodes and consequential functional impairment adhere to medications for at least two years.

The decision to continue medications for longer needs to be decided individually, weighing up past psychiatric history, other medical co-morbidities and risk factors along with the impact of relapse on the patient and family members. The risk factors stated above are known to increase the chance of relapse, making concordance to pharmacotherapy crucial among many. Some patients do however challenge the idea of taking maintenance medications when they are in remission and feeling well. Within consultation some may even confess that they have reduced the dose or discontinued medication entirely due to concern about potential or actual side-effects. It is important to reassure patients that antidepressants are effective in treatment and remission, are not addictive, do not lose efficacy over time and do not cause new long-term adverse effects.

If discontinuing medications is a priority for individuals who have gained good response or symptomatic remission, then it needs to be done gradually and under medical supervision. Needless to say, the non-medication part of recovery is equally important, ensuring people who have recovered are equipped with routines, activities and supports which maintain wellness, and that they are aware of relapse indicators and contingency plans, if needs be.

References

The full original article originally appeared in the Irish Medical Times in 2019. 

Alexopoulos, G. S. (2005). Depression in the elderly. The lancet, 365 (9475), 1961-1970.

Beekman, A. T., Copeland, J., and Prince, M. J. (1999). Review of community prevalence of depression in later life. The British Journal of Psychiatry, 174 (4), 307-311.

Engel GL. The need for a new medical model: a challenge for biomedicine. Science, 1977

Cambridge Textbook of Effective Treatments in Psychiatry, First Edition.

The Maudsley Prescribing Guidelines in Psychiatry, 13th Edition