In plain English
Depression and anxiety are both common in people with dementia and frequent mimics of dementia in people who do not have it. Recognising and treating them improves quality of life, cognition and family wellbeing. NICE-aligned treatment combines psychological therapy with medication where indicated.
Why mood matters in dementia
Depression and anxiety are present in 20 to 40 per cent of people with dementia at some point during the illness. They reduce quality of life, accelerate cognitive decline, increase carer burden, and contribute to behavioural and psychological symptoms. Treating them is one of the most impactful interventions available.
Equally important: depression is one of the most common reversible causes of cognitive complaints in older adults who do not have dementia. The traditional term "pseudodementia" refers to depression that produces a cognitive profile resembling dementia but which improves substantially when the depression is treated.
How to recognise depression in dementia
The classic features of depression (persistent low mood, loss of interest, sleep disturbance, change in appetite, tiredness, hopelessness, suicidal thoughts) all apply. In dementia, presentation is often subtly different:
- More apathy and reduced engagement than overt sadness;
- Increased irritability, agitation or tearfulness;
- Reduced appetite and weight loss;
- Sleep disturbance (early waking or insomnia);
- Pulling away from previously enjoyed activities;
- Increased somatic complaints (pain, fatigue).
Depression in dementia is often missed because some symptoms (apathy, sleep disturbance, withdrawal) overlap with dementia itself. A high index of suspicion, structured questioning, and use of validated scales (the Cornell Scale for Depression in Dementia is widely used) help.
How to recognise anxiety
Anxiety in dementia often appears as:
- Restlessness, pacing and repetitive questioning;
- Reluctance to be alone or new clinginess to a particular carer;
- Physical symptoms: trembling, breathlessness, palpitations;
- Worry about specific upcoming events (appointments, family visits);
- Fear of getting lost or of being left.
Anxiety frequently sits alongside depression. Both respond to the same first-line approaches.
Why depression mimics dementia
Severe depression in an older adult can produce a measurable cognitive impairment: slowed processing, reduced concentration, impaired working memory, poor performance on the Addenbrooke's Cognitive Examination. The Memory domain in the ACE-III may be particularly affected because of poor encoding effort, even though true memory consolidation is intact. The classic clue is that recognition on memory tasks is much better than free recall, suggesting retrieval rather than encoding is the problem.
Treating the depression often improves the ACE-III score by 5 to 15 points within 3 to 6 months. A repeat cognitive test after treatment is the most useful single step in clarifying the picture.
Assessment
A clinician evaluating low mood in suspected or established dementia typically:
- Takes a detailed history of mood, sleep, appetite, motivation, hopelessness and suicidal thoughts, ideally with collateral from family;
- Uses a screening tool: the PHQ-9 in mild dementia, the Cornell Scale in moderate to severe dementia;
- Reviews medications for depressogenic agents (some beta-blockers, steroids, opioids);
- Checks blood tests including thyroid function, B12 and folate;
- Considers physical contributors (chronic pain, untreated Sleep Apnoea, anaemia).
Treatment: NICE-aligned approach
Psychological therapy
NICE NG222 (depression in adults) recommends psychological therapy as a first-line option for mild and moderate depression. In dementia, modified cognitive behavioural therapy, behavioural activation, and life-review or Reminiscence Therapy can all help, particularly in mild to moderate dementia. Talking therapy may need to be brief, frequent, and modified for cognitive level.
Antidepressant medication
Selective Serotonin Reuptake Inhibitors are the usual first-line antidepressant in older adults. Sertraline and Citalopram are commonly chosen, starting at low dose and titrating. Mirtazapine is a useful option where sleep, appetite or anxiety are prominent. Trazodone, at low dose, is sometimes used for agitation with anxiety.
Antidepressants are not universally effective in established dementia. Trials in moderate to severe dementia have shown mixed results, with the HTA-SADD trial finding little overall benefit from Sertraline. In practice, a 12-week trial of an antidepressant is often justified where depression is plausible and impactful, with review at the end of the trial.
Behavioural and social
Activity, exercise, sunlight, social contact, and treatment of pain or Sleep Apnoea each improve mood independently of medication. See exercise and social engagement.
Suicidal thoughts
Suicidal thoughts are not uncommon in early dementia, particularly around the time of diagnosis. Specific risk factors include male sex, social isolation, alcohol misuse, recent loss, and a previous history of mood disorder. NICE NG97 recommends asking directly about suicidal thoughts as part of routine assessment.
If you or someone you support is having suicidal thoughts:
- Talk about it. Asking does not cause harm; it usually helps;
- Contact the GP or NHS 111 the same day, or 999 in immediate crisis;
- Samaritans 116 123 are available 24 hours a day.
Treating mood in someone with capacity changes
A person in moderate dementia may have reduced capacity to make complex treatment decisions. The Mental Capacity Act framework supports best-interests decisions, in consultation with family, an attorney for health and welfare, or an independent mental capacity advocate. See Mental Capacity Act and Lasting Power of Attorney.
When to seek specialist input
Three thresholds prompt referral to older adult psychiatry or your memory clinic:
- Severe depression with suicidal thoughts, self-neglect or significant weight loss;
- Mood symptoms not responding to 12 weeks of antidepressant treatment;
- Complex co-existing presentation (psychosis, prominent agitation, comorbid bipolar disorder).
The Dementia Service provides private memory clinic assessment that can be particularly useful where cognitive complaints may reflect depression rather than dementia, with the structured letter going to your GP to support continued care.
Frequently asked questions
Can depression cause dementia symptoms?
Severe depression in older adults can produce a measurable cognitive impairment that resembles dementia. Treating the depression often substantially improves cognition. This is sometimes called pseudodementia.
Are antidepressants effective in dementia?
The evidence is mixed in established dementia. In milder cases and in MCI they are often helpful. A 12-week trial with review is a reasonable approach where depression is plausible and impactful.
What is the Cornell Scale for Depression in Dementia?
A widely used 19-item scale, completed by a clinician with input from the person and a family member, designed to detect depression in dementia where standard self-report scales may not work well.
How do I talk about suicidal thoughts safely?
Ask directly. Asking does not increase risk and usually reduces it. If risk is present, contact the GP or NHS 111 the same day, or 999 in immediate crisis.
Does exercise help mood?
Yes. Regular physical activity is one of the most reliable mood interventions across the life course, including in mild to moderate dementia.
References
- NICE NG222: Depression in adults: treatment and management.
- NICE NG97: Dementia, assessment, management and support.
- Banerjee S et al. Sertraline or Mirtazapine for depression in dementia (HTA-SADD): a randomised, multicentre, double-blind, placebo-controlled trial. The Lancet 2011.
- Alexopoulos GS et al. Cornell Scale for Depression in Dementia. Biol Psychiatry 1988.