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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Antidepressants do not reduce symptoms of depression in people with dementia compared with placebo (dummy pills). Measured 6 to 13 weeks after starting the treatment, there is little or no difference in participants’ symptoms, but an increased chance of unwanted side effects. The review did not identify enough data to determine if antidepressants have an effect in the longer-term.
This Cochrane review included randomised controlled trials of any antidepressant drugs compared to placebo. Participants were aged 75 years on average, with mild or moderate dementia. The quality of the included trials was mixed, with not enough information reported to fully assess the risk of bias, though the main result is reliable.
This review supports the NICE guideline, which recommends that antidepressants are not routinely offered to people with dementia and depression, but that psychological treatments are considered instead.
Why was this study needed?
Dementia is a condition that includes memory loss, reasoning and communication difficulties, and changes in personality. It is progressive, so symptoms usually get worse. The most common types of dementia are Alzheimer’s disease and vascular dementia.
The number of people with dementia is increasing as people live longer. In December 2017, GP registers in the UK showed more than 450,000 people had a formal diagnosis of dementia. The total for all forms of diagnosed and undiagnosed dementia may be higher, as the Alzheimer's Society estimates there are currently around 850,000 people in the UK with dementia.
People with dementia often also have mood changes. While diagnosing depression in people with dementia can be difficult, studies have shown that 10-20% of people with Alzheimer’s disease have clinical depression. Antidepressants are often prescribed for people with dementia and depression, but it isn’t clear how effective they are in the presence of dementia. Many of the trials are small. This study aimed to combine results from appropriate trials to give a better picture of the likely effects of treatment.
What did this study do?
This Cochrane review found ten randomised controlled trials comparing antidepressants with placebo in 1,592 people diagnosed with dementia and depression using accepted criteria. Eight trials were included in the meta-analyses.
A variety of antidepressants were used. The trials used different outcome measures to assess changes in depression symptoms. Most of the trials lasted between 6 and 12 weeks; one continued for 39 weeks.
Only one trial took place in the UK, using community mental health teams. Other studies were conducted in outpatient clinics in the US, Brazil and Argentina. One study, in Austria, was carried out among inpatients and nursing home residents.
The trials were all double-blind, so neither the clinicians nor the participants knew which drug they were taking, which increases the reliability of the results. There was some uncertainty about the assessment of clinical recovery or remission, but any flaws would be unlikely to explain a lack of effect.
What did it find?
- There was little or no difference in depression scores between the antidepressant and placebo groups after 6 to 13 weeks (standardised mean difference [SMD] -0.10, 95% confidence interval [CI] -0.26 to 0.06; 8 studies, 614 participants, high-quality evidence).
- According to the Cornell Scale for Depression in Dementia (range 0 to 38), there was also no difference between groups after six to nine months (mean difference 0.59 points, 95% CI -1.12 to 2.30; 2 studies, 357 participants, moderate-quality evidence).
- More people (about one in five) taking antidepressants recovered from depression (the remission rate) by 6 to 13 weeks (antidepressant 40%, placebo 21.7%; odds ratio [OR] 2.57 (95% CI 1.44 to 4.59; 4 studies, 240 participants, moderate-quality evidence). However, only one trial continued to 24 weeks, and so it is unclear whether antidepressants have an effect on long-term remission.
- Antidepressants had no effect on people’s ability to carry out daily living tasks at 6 to 13 weeks (SMD -0.05, 95% CI -0.36 to 0.25; 4 studies, 173 participants, high-quality evidence).
- People taking antidepressants were more likely to suffer at least one adverse event than those on placebo treatment (antidepressant 49.2%, placebo 38.4%; OR 1.55, 95% CI 1.21 to 1.98; 3 studies, 1,073 participants).
What does current guidance say on this issue?
The NICE guideline published in June 2018 on the assessment and management of dementia has a section on managing non-cognitive symptoms. It suggests considering psychological treatments for people with mild to moderate dementia who have mild to moderate depression. It says that antidepressants should not be routinely offered unless they are indicated for a pre-existing severe mental health problem.
What are the implications?
This updated Cochrane review supports the advice that antidepressants should not be prescribed to treat depression in people living with dementia.
The previous version only included four studies, with a total of 137 participants. The additional six trials, with more participants, have strengthened the message and confidence in the finding. As the largest systematic review to date, it supports NICE guidance.
There wasn’t enough evidence to draw conclusions about any individual antidepressant, or about different types of dementia. There was also little evidence about the longer-term effects of antidepressants. Future research could focus on these areas to address any doubts about the applicability of this finding.
Citation and Funding
Dudas R, Malouf R, McCleery J and Dening T. Antidepressants for treating depression in dementia. Cochrane Database Syst Rev. 2018;(8):CD003944.
Cochrane UK and the Cochrane Dementia and Cognitive Impairment group are supported by NIHR infrastructure funding.
Bibliography
NHS website. Living well with dementia. London: Department of Health and Social Care; 2018.
NICE. Dementia: assessment, management and support for people living with dementia and their carers. NG97. London: National Institute for Health and Care Excellence; 2018.
NICE. Depression in adults: recognition and management. CG90. London: National Institute for Health and Care Excellence; 2009, updated 2018.
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