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These are activities that expand general practice knowledge, skills and attitudes, related to your scope of practice.
These are activities that require reflection on feedback about your work.
These are activities that use your work data to ensure quality results.
Overlapping symptoms can make it hard to distinguish between depression and dementia, and the two can co-occur, further complicating assessment.
Despite the challenges, however, there are signs to look out for and strategies you can use to help reach an accurate diagnosis.
The following factors are suggestive of dementia:
A new onset of depression in anyone under the age of 60 may in fact indicate early cognitive decline, explains geriatrician Associate Professor Michael Woodward AM, Dementia Australia Honorary Advisor and Director of the Aged Care Research and Memory Clinic, Austin Health.
“It’s more common for young people with early onset dementia to be diagnosed initially with a psychiatric disease,” he says.
“So somebody in their 50s who’s got clear changes in mood might actually be in the early stages of dementia, but they’ll be inappropriately diagnosed with depression or a psychotic disease or anxiety or attention deficit disorder.”
Antidepressant treatment resistance is another signal to review cognitive function, Associate Professor Woodward says.
“We know that not everybody who’s truly depressed does respond. But a red flag is if after 12 weeks of adequate doses, say 100 milligrams of sertraline or 30 to 60 milligrams of mirtazapine per day, if they haven’t responded, think to yourself, maybe this isn’t just depression.”
Symptoms such as depression and “even more particularly apathy and loss of interest,” can be early signs of a disease such as Alzheimer’s, Associate Professor Woodward says.
“So you would treat the depression, but watch them because over time, they may develop more clear features of cognitive decline.”
Approximately 50% of people with dementia will display apathy at some point, particularly in the advanced stages and in certain forms (such as frontal lobe dementia), adds consultant psychiatrist Steve Macfarlane, Associate Professor of Aged Psychiatry at Monash University and Head of Clinical Services for Dementia Support Australia.
“But if you ask somebody who’s just apathetic whether or not they feel depressed, they’ll usually say no. And usually when a pleasant activity is initiated they’ll still be able to enjoy participating,” Associate Professor Macfarlane says.
The DSM-5 states that for cognitive deficits to meet the criteria for a major neurocognitive disorder, they cannot be primarily attributable to another mental disorder (such as depression).
It can be tricky to work through that, so Dr Marita Long, Clinical Associate Professor at the University of Tasmania’s Wicking Dementia Research Education Centre and medical advisor for Dementia Australia, recommends that GPs assess for and treat any existing depression first.
“Excluding or treating depression is an important part of the diagnostic workup for anyone with a suspected cognitive disorder,” Dr Long says.
“Once the depression has been treated and the person has returned to baseline (or as close as possible) it is important to go back and reassess cognition,” she adds.
“Equally, a cognitive disorder should be considered if depression doesn’t follow the usual pattern—such as if significant behavioural changes are present—or if it doesn’t respond to treatment.”
However, Associate Professor McFarlane and Professor Woodward say it’s not always black and white.
“A mild case of depression can usually be reliably differentiated from dementia on the basis of the length of the history,” Associate Professor McFarlane says. “Having said this, if someone comes to me with cognitive concerns, but their evaluation indicates that the primary problem is, indeed, depression, I’d agree that dementia should not be diagnosed until the depression has been adequately treated.”
Professor Woodward agrees.
“In essence, dual pathology is far from rare. It is true that treatment of depression may resolve cognitive symptoms, but often both conditions are present and the clear history and findings of dementia/MCI can be ascertained even in a depressed person,” he says, adding that biomarkers will soon make it easier to spot underlying Alzheimer’s pathology even in a depressed person.
Depression can also present as a cognitive disorder.
“It works both ways,” Associate Professor Woodward says.
“So you need to probe deeply. When did this come on? Was there any family history of dementia? Were they clearly forgetful for some years? Have they been repeating themselves? Have they been misplacing objects? Have they been forgetting recent information?”
“And if the answer to all those is no, but for the last three months they’ve been lying in bed, unwilling to do anything, it is more likely they have depression or another treatable medical disorder.”
Associate Professor Macfarlane also notes that older patients are less likely to report low mood and may instead say they feel anxious or worried.
“So be on the lookout for anxiety as a differential for depression in older people and in those with dementia as well.”
Recent cognitive change may suggest a depression syndrome.
“Depression evolves over days to weeks to months whereas dementia gets worse over months to years,” Associate Professor Macfarlane says.
“So if they had an MMSE or a MoCA score of 30 out of 30 six months ago and now they’re sitting at 22, there’s a reasonable possibility that that change in that period of time might be due to a depression rather than a dementia.”
Difficulty registering (immediately repeating back) the three words in the MMSE (or five in the MoCA) is “often due to an attentional deficit, which is much more common with depression than with dementia,” Associate Professor Woodward says.
“So very simplistically, depression, you ask them to say the three words and even after five trials, they can’t get them. They have trouble registering them. Whereas with dementia, they usually immediately get the three words––they say them back correctly—and then one or two minutes later they’ve forgotten them…. That’s not always true, but that’s a good rule of thumb.”
“Likewise, when you’re doing the serial sevens, and they just can’t do it—they might say 100, 90, 97, 60—they’re all over the place. That can happen with a cognitive disorder, but again it’s suggestive that they might have a depression and therefore their attention can’t be focused.”
“If you ask somebody with a cognitive disorder ‘what’s the date today?’, they’ll truly not know,” Associate Professor Woodard says. “If they’ve got depression, they’re much more likely to say, ‘It’s not important. I don’t care’.”
“So lots of ‘I don’t care. I don’t need to know’—think about depression. Lots of trying to get the right answer, but clearly not knowing the answer—think about a cognitive disorder.”
People with dementia are at higher risk of depression, but it can become increasingly difficult to recognise as dementia progresses, says Associate Professor Macfarlane. There is no validated test to screen for depression in someone with severe cognitive dysfunction.
Nor is there expert consensus about what constitutes depression in dementia.
So, what can you do?
You may need to ask several times, but if someone can answer yes or no, “that’s a reasonable back of the envelope judgment about the likelihood of an underlying depression,” Associate Professor Macfarlane says.
Facial expression, tone of voice and reduced spontaneous speech can signify depression, he adds, as can self-harm attempts, sleep disturbances (usually insomnia) and appetite disturbances, which can be monitored in residential care.
Reduced interest in enjoyable activities is another signal.
“Even in the setting of an advanced dementia it’s often possible to get a positive emotional response from things like a visit from grandchildren or friends,” Associate Professor Macfarlane says.
“If that’s recently been lost, that’s another observable thing you could use to infer that a depression is perhaps more likely.”
While we lack evidence that antidepressants work as well in people with severe dementia, Associate Professor Macfarlane believes they can, noting they top the list of pharmacological strategies for managing changed behaviours.
“If you’re not sure whether a behavioural change represents depression or not, a trial of an antidepressant is more likely to produce an effect than an antipsychotic is—and it’s a lot safer,” he says.
“That’s not because antidepressants have any magical effect on behaviour as such, but it probably reflects the fact that a proportion of changed behaviour is due to unrecognised depression.”
The 15-point Geriatric Depression Scale can be very useful, Associate Professor Woodard says. A score of 7 or more suggests probable depression.
Conditions including hypothyroidism, low haemoglobin, electrolyte disturbances and cardiac conduction deficits can cause depression and cognitive symptoms, Associate Professor Woodward notes, recommending the following investigations to exclude them.
Increasingly, blood-based biomarkers are also being used in research settings to diagnose the presence of such pathology and are likely to be available in non-research settings soon, Professor Woodward adds.
The MMSE is not sensitive enough to pick up subtle cognitive decline, Associate Professor Woodward notes. “The MoCA (Montral Cognitive Assessment) is the far better test.”
You need to complete a free one-hour training module to administer the MoCA.
Cognitive assessment can be abnormal in people with true depression, Associate Professor Woodward says.
“But usually, if their MoCA is low, say 22, 21, and even if they’re depressed, it’s likely that they also have a significant cognitive disorder.”
MRI and PET scans are usually needed to confirm underlying neurocognitive pathologies such as Alzheimer’s, Associate Professor Woodard says. “And that’s usually going to be by referral to a specialist.”
Delirium can also cause symptoms that mimic dementia or depression – and dementia and depression increase the risk of delirium. Key features of delirium include sudden onset (over hours or days) and fluctuating symptoms. It is often triggered by acute illness or injury, surgery or medication, and is very common during or just after a hospital stay.
It’s particularly important to rule out dementia with Lewy bodies, which can present with an unexplained delirium. While symptoms can be the same, haloperidol and other antipsychotics sometimes used in a delirious patient are contraindicated in people with Lewy body dementia due to the risk of severe movement disturbances (such as spasms or rigidity).
Associate Professor Woodward advises a low index of suspicion for cognitive disorders.
“Don’t hesitate to refer to a specialist. I regularly see people who have been diagnosed with depression … and it’s clear to me with the benefit of hindsight that they’ve probably had the early features of a cognitive disorder for years.”
He suggests referring people to a geriatrician, neurologist or psychiatrist with an interest in dementia if they have:
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