Review of Non-Pharmacological Sleep Interventions for Depression

This report presents a critical appraisal of a literature review and meta-analysis published in Sleep Medicine Reviews (2019) that investigated the impact of non-pharmacological sleep interventions on depression symptoms. The review aimed to synthesize findings from randomized controlled trials (...Read More

Running head: Critical Appraisal Literature Review 1
Critical Appraisal Literature Review
Author’s name
Institutional Affiliation

Critical Appraisal Literature Review 2
1. What is the review purpose, objective or question?
The primary purpose of the review was to identify and synthesize the results obtained
from various randomized controlled trials of non-pharmacological interventions meant to
improve sleep in depression patients. Additionally, the review also aimed to examine whether
such sleep improvements in patients with depression were of high quality in order to determine
whether heterogeneity in the effect of sleep intervention can be expounded by variation in how
effective the strategy is in improving perceived sleep quantity.
2. Was there a published protocol for this review? If yes - please provide the reference
The article was published, approved and posted by Elsevier publishers under Sleep Medicine
Reviews in the year 2019. Below is the review reference.
Gee, B., Orchard, F., Clarke, E., Joy, A., Clarke, T., & Reynolds, S. (2019). The effect of non-
pharmacological sleep interventions on depression symptoms: A meta-analysis of
randomized controlled trials. Sleep Medicine Reviews, 43, 118-128.
DOI:10.1016/j.smrv.2018.09.004
3. What are the inclusion criteria for this review?
The inclusion criteria for trial interventions included any non-pharmacological strategy
that leads to sleep improvement in patients with depression as controlled by conditions that were
not designed to improve sleep. In addition, only articles that were in the English language and
measured the depression symptoms using a validated instrument were included. Articles that had
pharmacological interventions to improve sleep or a control group received any intervention to

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improve sleep were excluded from the review. Furthermore, the review excluded all articles
with sleep interventions were designed to improve fatigue, sleep apnoea or parasomnias.
4. What types of studies were included?
Only randomized control trial studies were included in the review.
5. What databases/search engines were searched?
The databases that were used during the search included CINAHL, CENTRAL, Medline and
PsycINFO.
6. Were the search terms suitable for the purpose of this review?
The search terms were suitable for this review as they directly or closely related and addressed
the review topic accordingly. Such terms included sleep, insomnia, sleep treatment, sleep
disorders, help, support, hygiene, education, depression, and mood. Boolean terms OR, AND
were used together with search terms.
7. What search limits were applied?
The limiters included all articles published until 2018 with the oldest published in the year 1998
and the latest in 2017. The limiters also included clinical trials and English publications.
8. Does the PRISMA flowchart adequately describe how articles were identified,
screened, assessed for eligibility, appraised and selected for inclusion in the review?

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The PRISM flowchart properly demonstrates how articles were identified, screened,
assessed for eligibility, appraised and included for the review. All the records identified from
databases were 2969 articles and additional 5 studies from manual searching. The records
removed after duplicates included 2508 articles where 1985 records were excluded after
screening as they consisted of titles and abstracts only. The remaining 124 full-text articles were
assessed for eligibility. In this category, 63 full-text articles were excluded. The reasons for
exclusion included control conditions design for sleep, depression not measured as an outcome
and those which had interventions not designed to improve sleep. Therefore, 61 studies were
eligible for inclusion criteria. However, 3 articles had samples that overlapped with another and
9 articles had inadequate depression data thus only 49 articles were used in the meta-analysis.
9. What critical appraisal instrument(s) was/were used to determine the methodological
quality of the articles? Were these instruments appropriate?
The review used the Cochrane collaboration's risk of bias tool in determining the
methodological quality of the articles used specifically in checking the bias of the studies to
ensure quality and consisted of results were obtained. The Cochrane collaboration's risk of bias
tool was appropriate for this review as it is usually suitable in assessing risk bias in randomized
trials(Higgins et al., 2011). This bias tool usually contains six domains which include selection
bias, detection bias, performance bias, attrition bias, reporting bias and other bias that tend to
help researchers in determining the extent of quality to prevent hasty generalization, inadequate
selection, poor data presentation thus resulting to reporting of consistent and evidence-based
results that can be used in clinical practice(Higgins et al., 2011).

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10. Are the included studies summarised adequately? (Study type, study population,
location, interventions, outcomes, results)
Although the included data have been summarized using a data extraction table in six categories
which include study name, country, participants involved, interventions used, depression
measure methods and sleep measure, other parameters of summarizing articles have been
excluded. These include sample used, outcomes of each study and their results.
11. Are excluded studies listed with reasons for their exclusion?
The excluded studies have been listed in the PRISM flowchart and search strategy with a
specific number and their reasons. 1985 records were excluded after screening as they consisted
of titles and abstracts only. 63 full-text articles were excluded due to reasons such as control
conditions design for sleep, depression not measured as an outcome and those which had
interventions not designed to improve sleep. Three articles were excluded since they had samples
that overlapped with another and 9 articles were excluded as they had inadequate depression
data.
12. How was the data abstracted and synthesized?
The data from this review was abstracted and synthesized using subgroup analysis and
meta-regression. Data was analyzed into co-morbid mental health difficulties to determine the
pooled effect of depression and heterogeneity across studies. Data was also abstracted according
to age which included adolescents, adults and older adults using measures of the standard

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deviation to enhance interpenetration. Depression measure was calculated using various tools
such as epidemiological studies depression scale(CESD), Beck depression inventory(BDI),
hospital anxiety and depression scale(HADS), nine-item patient health questionnaire(PQH-9),
and the Beck depression inventory version 11. Data were synthesized using mean, standard
deviation, weight, and mean the difference in the various subgroups. The presentation of data
was in form of graphs and tables.
13. Is there an adequate critique of the studies reviewed, including a discussion of study
limitations?
One of the major limitations of the study highlighted is that the diagnostic criteria of
depression include sleep problems as a symptom and therefore when measuring depression, sleep
is incorporated as one item assessing depression. Since such items account for a small proportion
of the scale score it is unlikely that change of such items after sleep problems are treated can
account for effects observed. However, when such an item level is missed it could be
impossible to distinguish the strategies trialed on non-sleep depression symptoms. Another
limitation of the review was that many studies involved in meta-analysis excluded individuals
with major depression thus the pooled effects cannot be determined properly.
14. Were the levels of evidence reported in this systematic review? What is your
assessment of the level of evidence included in this review?
Although the level of evidence has not been mentioned directly, all articles in the review
are randomized controlled trials. Random control trials(RCTs) falls under the first level of

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evidence. RCTs are considered to be at the top level of evidence in clinical practice due to their
robustness and confidence in producing data(Guerrera, Renaud, Tabbò, & Filosso, 2017).
Additionally, RCTs allow the elimination of many pre-analytical differences that might bring
bias to the whole study(Guerrera et al., 2017). In this regard, the review is of a high level of
evidence as it consists of results that are from high-quality studies.
15. How should the information from this systematic review be applied in clinical practice
(knowledge transfer)
Depression management currently has limited interventions that are successful in the
treatment of various symptoms including sleep. This is because most of the pharmacological
interventions offered in sleep improvements are usually associated with stigma. Offering non-
pharmacological interventions means patients will experience low stigma thus reducing mental
health difficulties and improving patients sleeping patterns. Additionally, such treatments can
help people who have specific depression drugs that are not compatible with pharmacological
sleep improvement treatments. Other than that, non-pharmacological sleep interventions have a
lower cost and thus can be used as treatment options.

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References.
Guerrera, F., Renaud, S., Tabbò, F., & Filosso, P. L. (2017). How to design a randomized
clinical trial: Tips and tricks for conducting a successful study in the thoracic disease
domain. Journal of Thoracic Disease, 9(8), 2692–2696.
https://doi.org/10.21037/jtd.2017.06.147
Gee, B., Orchard, F., Clarke, E., Joy, A., Clarke, T., & Reynolds, S. (2019). The effect of non-
pharmacological sleep interventions on depression symptoms: A meta-analysis of
randomized controlled trials. Sleep Medicine Reviews, 43, 118-128.
DOI:10.1016/j.smrv.2018.09.004
Higgins, J. P. T., Altman, D. G., Gøtzsche, P. C., Jüni, P., Moher, D., Oxman, A. D., … Sterne,
J. A. C. (2011). The Cochrane Collaboration's tool for assessing the risk of bias in
randomized trials. BMJ (Online), 343(7829). https://doi.org/10.1136/bmj.d5928

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