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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Preventing the incidence of new cases of mental disorders: a meta-analytic review

P Cuijpers, A Van Straten, and F Smit.

Review published: 2005.

CRD summary

This review assessed the effects of preventive interventions on mental disorders. The authors concluded that it appears possible to prevent new cases. The evidence seems to support the authors' general conclusion. However, the limited number of studies, which varied considerably in participants and interventions, and the lack of reporting of some review methodology make the reliability of the results uncertain.

Authors' objectives

To assess the effects of preventive interventions on the incidence of new cases of mental disorders.

Searching

MEDLINE, PsycINFO and ERIC were searched from 1980 to August 2002; the keywords were reported. The bibliographies of meta-analyses, reviews and included studies were checked.

Study selection

Study designs of evaluations included in the review

Randomised controlled trials (RCTs) with pre- and post-test data, or studies with data on reduction in specific life events with only post-test measurement of mental disorder, were eligible for inclusion.

Specific interventions included in the review

Studies that compared preventive interventions or interventions aimed at reducing the results of specific, traumatic life events with a no-intervention control were eligible for inclusion. The interventions assessed in the included studies were group sessions, debriefing, counselling, cognitive-behaviour therapy, parent training, conflict reduction, coping and interpersonal therapy.

Participants included in the review

Studies of people who had had mental illness excluded by a diagnostic interview, or who had experienced a specific, traumatic life event without prior assessment, were eligible for inclusion. The participants in the included studies were people with depressive symptoms, adolescents with subclinical depression, primary school children with subclinical anxiety, patients at risk of psychosis, university students with a high Attributional Style Questionnaire score, women at risk for postpartum depression, children of divorced parents, general practitioner (GP) patients without major depressive disorder, and patients who had experienced burns trauma, road traffic accidents and violent crime.

Outcomes assessed in the review

Studies that assessed new cases of mental disorders using a standardised diagnostic interview were eligible for inclusion. The diagnostic tools used in the included studies were not reported.

How were decisions on the relevance of primary studies made?

Two reviewers independently selected studies and resolved any disagreements through discussion.

Assessment of study quality

Study quality was assessed in relation to randomisation, outcome measures used, presence of theoretical basis for the intervention, and adequacy of statistical analyses. The authors did not state who performed the quality assessment.

Data extraction

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

For each study, the reviewers calculated the incidence rate of mental disorder in person-months and used this to calculate the person-years incidence rate. They also calculated the relative risk (RR) and 95% confidence intervals (CIs) of developing a mental disorder for each study for the intervention versus the control.

Methods of synthesis

How were the studies combined?

Pooled RRs and 95% CIs were calculated using both a random-effects model (DerSimonian and Laird) and a fixed-effect model. Since the results were similar, only the results for the random-effects model were presented. The fail-safe number (N) of studies was calculated for all studies, cognitive-behavioural studies and indicated intervention studies.

How were differences between studies investigated?

Statistical heterogeneity was assessed using the chi-squared statistic. Meta-analyses were performed with and without one study in which the control group was a 'needs-based' intervention. Since the results were similar, the results were reported for when this study was included.

A subgroup analysis was used to explore the effect on the results of the specific disorder (depression or post-traumatic stress disorder), type of intervention (cognitive-behaviour therapy or debriefing) and type of prevention (indicated or selective prevention). The meta-analysis was repeated after excluding each of two large RCTs in turn.

Results of the review

Thirteen RCTs (n=1,570) with sixteen treatment comparisons were included. The period of follow-up ranged from 99 days to 6 years.

All studies were considered to be of a high quality, using well-validated measures, well-described and theoretically well-founded interventions, and adequate statistical analyses.

All studies.

The intervention statistically significantly reduced the risk of developing a mental disorder compared with the control (RR 0.73, 95% CI: 0.56, 0.95). The fail-safe N was 13.

Prevention of specific disorders.

There was a statistically significant reduction in the risk of developing a depressive disorder (including postpartuum depression) with the intervention compared with control (7 RCTs; RR 0.72, 95% CI: 0.54, 0.96). There was an increased risk of developing post-traumatic stress disorder with the intervention compared with the control which was not statistically significant (4 RCTs; RR 1.33, 95% CI: 0.75, 2.37).

Type of intervention.

There was a statistically significant reduction in the risk of developing depression or anxiety disorder (including postpartuum depression) with cognitive-behavioural interventions compared with controls (7 RCTs; RR 0.69, 95% CI: 0.53, 0.89). The fail-safe N was 8. There was an increased risk of developing post-traumatic stress disorder with debriefing compared with the control which was not statistically significant (4 RCTs; RR 1.33, 95% CI: 0.75, 2.37).

Level of prevention.

There was a reduced risk of developing a mental disorder with selective prevention compared with the control which was not statistically significant (11 RCTs; RR 0.81, 95% CI: 0.59, 1.11). There was a statistically significant reduction in the risk of developing a mental disorder with indicated prevention compared with the control (5 RCTs; RR 0.58, 95% CI: 0.37, 0.92). The fail-safe N was 2.

No statistically significant heterogeneity was detected for any of the analyses.

Authors' conclusions

The prevention of new cases of mental disorders seemed possible.

CRD commentary

The review addressed a clear question in terms of the participants, intervention, outcomes and study design. Several relevant sources were searched but no attempts were made to locate unpublished studies, thus raising the possibility of publication bias. It was unclear whether any language restrictions had been applied. Two reviewers independently selected the studies, thus reducing the potential for selection bias. However, the methods used to assess quality and extract the data were not described, so it is not known whether any efforts were made to reduce errors and bias during these stages of the review. Only RCTs were included. Quality was assessed using specified criteria, but blinding of the outcome assessors and drop-outs was not reported.

The studies were pooled in a meta-analysis and statistical heterogeneity was assessed. Given the clinical heterogeneity among studies with respect to interventions and participants, it is questionable whether pooling studies was appropriate, even though no statistical heterogeneity was detected. Subgroup analyses were used to explore the influence on the results of various aspects of the interventions. The evidence appears to support the authors' general conclusion, although the positive effect for interventions was not seen in all subgroups studied. However, the limited number of studies, which varied considerably in participants and interventions, and the lack of reporting of some review methodology, make the reliability of the results of the review uncertain.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that more adequately powered studies are required to examine the effects of cognitive-behavioural interventions for the prevention of anxiety and depression, as well as the effects of selective interventions and indicated interventions. They further stated that future RCTs should focus on indicated prevention of common mental disorders in target groups with high incidence rates.

Bibliographic details

Cuijpers P, Van Straten A, Smit F. Preventing the incidence of new cases of mental disorders: a meta-analytic review. Journal of Nervous and Mental Disease 2005; 193(2): 119-125. [PubMed: 15684914]

PubMedID

15684914

Indexing Status

Subject indexing assigned by NLM

MeSH

Adolescent; Adult; Aged; Antidepressive Agents /therapeutic use; Anxiety Disorders; Child; Cognitive Therapy; Crisis Intervention; Depressive Disorder /epidemiology /prevention & control; Female; Humans; Incidence; Male; Mental Disorders /epidemiology /prevention & control; Middle Aged; Pregnancy; Preventive Health Services; Psychotherapy; Psychotherapy, Group; Psychotropic Drugs /therapeutic use; Randomized Controlled Trials as Topic; Risk; Stress Disorders, Post-Traumatic /epidemiology /prevention & control

AccessionNumber

12005003397

Date bibliographic record published

28/02/2006

Date abstract record published

28/02/2006

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 15684914

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