Depression in later life is common, treatable, and still routinely missed. Part of the reason is that it turns up wearing a disguise: poor sleep, aches no scan explains, a shrinking appetite, a slow withdrawal from things that used to matter. When it is recognised, the conversation usually moves quickly to medication. That is not a bad thing. Antidepressants help a great many people. But they behave differently in a body over 50 than they do at 30, and almost nobody is told that at the point of the prescription. This is not an argument against taking them. It is an argument for taking them well.
TL;DR
- Antidepressants work at any age, but doses and monitoring change after 65. Citalopram is capped at 20mg daily and escitalopram at 10mg daily in people over 65, because of a dose-dependent effect on heart rhythm.
- Low blood sodium (hyponatraemia) is the side effect most people are never warned about. Risk peaks in the first two weeks and rises sharply if you also take a diuretic, or “water tablet”.
- SSRIs are listed as fall-risk-inducing drugs in Ireland’s STOPP/START version 3 criteria, and have a mild antiplatelet effect that matters alongside anti-inflammatories or blood thinners.
- Give any antidepressant four to six weeks at an adequate dose before deciding it has failed, then continue six to twelve months after you feel well.
- Never stop abruptly. Current guidance is a slow, proportional taper with smaller steps as the dose gets lower.
Why the same tablet behaves differently after 50
Two things change with age. The liver and kidneys clear medicines more slowly, so the same dose produces a higher concentration and holds it there longer. And most people over 65 are not taking one medicine, they are taking five or six. Antidepressants do not arrive in an empty room. Irish general practice data shows antidepressant use among medical card holders rose from 9.42 to 12.3 per 100 patients between 2016 and 2020, with the highest rates in practices serving more patients aged 65 and over.
The dose rules that changed
Citalopram and escitalopram, two of the most commonly prescribed SSRIs, prolong the QT interval in a dose-dependent way. That is a measure of how long the heart takes to reset between beats, and stretching it too far can, rarely, trigger a dangerous rhythm. Regulators lowered the ceiling for older adults accordingly: a maximum of 20mg a day for citalopram and 10mg a day for escitalopram over the age of 65, lower again where liver function is impaired. Neither suits anyone with a known long QT syndrome or taking other QT-prolonging medicines.
This matters because old prescriptions sometimes simply carry on. If you have been on 40mg of citalopram since your fifties and you are now 70, raise it at your next review.
The side effect nobody mentions: low sodium
SSRIs and SNRIs can cause the body to hold on to too much water, diluting the blood’s sodium. Estimates of how often vary widely, but the pattern is consistent: risk concentrates in the first two weeks and stays elevated for the first few months. It is easy to miss because the symptoms look exactly like the depression being treated, or like ordinary ageing: tiredness, confusion, headache, nausea, cramps, unsteadiness. Severe cases cause seizures. Those most at risk are over 65, female, of lower body weight, taking a diuretic, or already at the low end of the normal range.
Standard practice is a sodium check before starting and a repeat at around two weeks. A 2024 analysis found testing in the first week did not reduce hyponatraemia-related hospital visits, so timing matters as much as the test itself. If you feel notably foggier or unsteadier in the fortnight after starting, ring the surgery rather than wait it out.
Falls, bleeding and interactions
The STOPP/START criteria are an Irish contribution to global prescribing safety, developed by Professor Denis O’Mahony’s team at University College Cork. Version 3, published in 2023, expanded to 190 criteria and added a group covering fall-risk-inducing drugs. Antidepressants are on that list, alongside opioids, sedating antihistamines and alpha-blockers.
SSRIs also appear in the coagulation section, because they reduce the ability of platelets to clump. Alone this is minor. Combined with a regular anti-inflammatory such as ibuprofen or diclofenac, or with an anticoagulant, it raises the risk of gastrointestinal bleeding. A free community pharmacist medicines review is a straightforward way to have someone check the whole list.
How long is long enough
Antidepressants are slow. Sleep and appetite may improve within a fortnight, but the mood effect usually needs four to six weeks at an adequate dose. Stopping at week three because “it is not working” is the most common way a treatment that would have worked gets discarded.
Once you feel well, continue for at least six to twelve months, because stopping at the point of recovery carries a high relapse rate. After several episodes, longer maintenance is often right. The corollary holds too: a prescription that has quietly renewed itself for eight years deserves a proper review, not automatic continuation and not an abrupt stop.
Coming off them properly
Guidance has shifted most here. NICE updated its position in 2022 and now recommends reducing in steps, prescribing a proportion of the previous dose each time, for example 50%, with smaller reductions such as 25% as the dose gets lower. Medicines with a short half-life need slower tapers, and each reduction should be held until withdrawal effects settle.
Those effects are real and were underestimated for years: dizziness, electric-shock sensations, irritability, vivid dreams, nausea, flu-like aching. For some they are mild and brief. For others they last months. Crucially they are not the same as depression returning. Withdrawal effects typically appear within days of a reduction and ease with a small increase, while relapse builds gradually over weeks. So: do not do this alone, do not do it fast, and do not do it in the middle of a bereavement, a house move or a hospital admission.
Medication is not the whole plan
Talking therapy works well in later life, and nothing in the evidence says people over 70 benefit less. Access is the harder part. Counselling in Primary Care offers up to eight free sessions on GP referral for medical card holders, but demand has outpaced supply: as of August 2026, close to 6,000 adults were waiting nationally, 1,768 of them for more than six months.
While you wait, use what is there. Aware runs a free support line on 1800 80 48 48, seven days a week from 10am to 10pm, plus free support and self-care groups. Samaritans is on 116 123, free and around the clock. Structured exercise, social prescribing through your GP or local link worker, and the plain discipline of a daily routine all have genuine evidence behind them, and none of them interact with your other tablets.
Questions for your next review
- Is this dose still appropriate for my age, particularly if it is citalopram or escitalopram?
- Has my sodium been checked since I started, and does anything else I take affect it?
- Does this interact with my anti-inflammatories, blood thinners or heart medicines?
- Could it be contributing to unsteadiness or a recent fall?
- How long is the plan to stay on it, and if we stop, how slow will the taper be?
None of this is a reason to be afraid of antidepressants. Untreated depression in later life carries its own heavy costs: physical decline, isolation, poorer outcomes from every other condition you have. The goal is not fewer prescriptions. It is better-monitored ones, reviewed on purpose rather than by default.
At Críonna Health we write about ageing well in Ireland, including the parts of healthcare that go unexplained. A ten-minute conversation about a medicine you have taken for years is rarely wasted.
This article is general information, not medical advice. Do not start, change or stop any prescribed medicine without speaking to your GP or pharmacist. If you are in crisis, contact your GP, call 112 or 999, or ring Samaritans free on 116 123.
📷 Photo by Ariel Salgado on Unsplash
