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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.
Workplace-based interventions for people with depressive symptoms are effective. This review of 16 trials looked at early stage interventions to prevent depressive symptoms from developing into more severe depressive illness.
Both cognitive behavioural therapy and some non-cognitive behavioural therapy interventions, such as supervised exercise, worked equally well. Telephone and internet-based therapy worked better than face-to-face therapy. These interventions were compared to usual treatment or being placed on a waiting list.
Given the prevalence of depression in the workplace, and its high cost to productivity, these findings should be considered by employers wishing to prevent the progression of depressive symptoms in their workforce. This must include provisions to safeguard patient confidentiality and is likely to require training of managers and workplace supervisors.
Why was this study needed?
About 2.6% of adults have a depressive episode in the UK at any one time, rising to 11.4% with the wider definition of mixed depression and anxiety. People with depression are most likely to be aged 35 to 54, and depression diagnoses are more common among women than men.
Estimates of the cost of depression vary, but one review put annual costs at around £7.5 billion, with lost employment accounting for £5.8 billion. Not only are people with depression more likely than their peers without depression to be absent from work, but they are also likely to be less productive when they are present.
Despite the costs of depression, evidence about the effectiveness of workplace interventions to prevent depression is limited.
What did this study do?
This systematic review and meta-analysis of 16 randomised controlled trials compared workplace interventions for depressive symptoms with usual care or waiting list controls. It included 2,522 adults with depressive symptoms, identified in the workplace.
Five trials were from the Netherlands, four from Japan, four from the UK and one each from the US, Australia and Finland. Interventions mainly included cognitive behavioural therapy (CBT) delivered by telephone, internet or in person, enhancing mental health literacy, exercise programmes and web-based self-help interventions.
Median follow-up time was four months, ranging from four weeks to three years. Depressive symptoms were self-reported using validated questionnaires such as the Patient Health Questionnaire. There was no economic analysis.
The results should be treated with caution as there was variability between studies and high risk of bias.
What did it find?
- Overall, workplace interventions targeting depressive symptoms had a small to moderate effect compared to control groups (standardised mean difference [SMD] ‑0.40, 95% confidence interval [CI] -0.54 to -0.25, 15 trials, 2,522 participants).
- Cognitive behavioural therapy-based interventions were moderately effective (SMD ‑0.44, 95% CI ‑0.61 to ‑0.26; 10 trials, 3,134 participants).
- The most effective intervention in the review was two sessions of supervised exercise a week for 10 consecutive weeks (SMD -1.32, 95% CI -2.16 to -0.48) but this was only based on 30 workers. The other exercise trial of 73 people using cardiovascular gym equipment three times per week did not have a significant effect on depressive symptoms.
- Interventions delivered by telephone or computer had a greater effect in reducing symptoms than in-person interventions, according to a meta-regression analysis (SMD for telephone -0.80, 95% CI -1.04 to -0.56; SMD for computer -0.36, 95% CI -0.53 to -0.18; SMD for in-person -0.17, 95% CI -0.46 to 0.13). No other study variables affected the effectiveness of the interventions.
What does current guidance say on this issue?
The NICE 2009 guideline on identification and management of depression in adults (updated in 2018) does not specifically address interventions that could be delivered in the workplace.
It does recommend guided self-help based on CBT including computerised CBT and CBT by telephone for people with persistent sub-clinical depressive symptoms or mild to moderate depression.
Group physical activity programmes are also recommended for people with persistent sub-clinical depressive symptoms or mild to moderate depression.
What are the implications?
The types of interventions assessed, such as programmes based on CBT and physical exercise, already have an evidence base for managing symptoms of depression in a healthcare setting. The novel finding is that they may also be helpful in the workplace.
It will be important to identify people likely to benefit in ways that do not compromise their confidentiality and to ensure that suitable interventions are offered in an appropriate manner.
The finding from this review are encouraging for employers in terms of the likely low cost but importantly are also effective options with the potential to improve productivity.
Citation and Funding
Nigatu YT, Huang J, Rao S et al. Indicated prevention interventions in the workplace for depressive symptoms: a systematic review and meta-analysis. Am J Prev Med. 2019;56(1):e23-e33.
The study was funded by the Canadian Institutes of Health Research and Movember Foundation.
Bibliography
NICE. Depression in adults: recognition and management. CG90. London: National Institute for Health and Care Excellence; 2009, updated 2018.
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