Study design
We shall conduct a systematic review and meta-analysis and we will report the outcomes according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement [26] following the guidelines in the Cochrane Handbook for Systematic Reviews of Interventions [27].
Search strategy
The literature search strategy is included in Additional file 1. The following search limits will be set: 1) Study design: randomised controlled trials (RCTs) and quasi-experimental studies, 2) limited to English language. Date restrictions will not be applied. The following bibliographic databases will be searched:
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▪ Cochrane Central Register of Controlled Trials
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▪ CINAHL (Cumulative Index to Nursing and Allied ? Health Literature)
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▪ EMBASE
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▪ MEDLINE
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▪ PsychINFO
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▪ SCI (Science Citation Index)
Grey literature
Search terms
We shall use Medical Subject Headings (MeSH) and free-text word terms, as appropriate to the databases. The electronic search strategy terms (where necessary using wildcards) are:
Social anxiety
Social phobia
Social anxiety disorder
Schizophrenia
Psychosis
Cognitive therapy
CBT
Effectiveness
Treatment efficacy
Search strategies will be pilot tested. We shall use EndNote to record titles and abstracts for retrieval and inclusion/exclusion decisions.
Selection criteria
Types of participants
Participants will be between 16 and 65 years of age, with schizophrenia or related psychoses (as diagnosed using any recognized diagnostic criteria) with social anxiety disorder as diagnosed using any recognised diagnostic criteria, for example, ICD-10 [28] or DSM-5 [2]. Studies including participants <16 yrs or >65 yrs or participants with a primary diagnosis of organic brain disorder will be excluded from this review.
Types of studies
RCTs and quasi-experimental studies will be included in the review.
Types of intervention
The review will include cognitive-behavioural (or cognitive) interventions that are targeted at social anxiety in people with psychosis. There will be no limitation in terms of psychological theory informing the intervention, the person delivering the intervention or the setting in which the intervention is delivered. Group and one-to-one interventions will be included.
Comparator
Control conditions will include any other treatment, no treatment, treatment-as-usual and a waiting list control.
Types of outcomes
Primary outcome
Eligible studies will have as primary outcome social anxiety (continuous data) measured using any psychometrically validated scale, both self-reported and clinician administered.
Secondary outcomes
These will include general anxiety symptoms, distress, depression, positive and negative symptoms of schizophrenia and quality of life measured using any psychometrically validated scale both self-reported and clinician administered, and the cost of CBT intervention (with another treatment or treatment-as-usual).
Selection procedure
Two researchers (MM and LT) will independently screen the title and abstract of retrieved references for inclusion. The full text of all potential eligible studies will be obtained by MM. The next step will involve two researchers (MM and LT) independently assessing obtained references for inclusion. We shall pilot test the procedure on a small number of studies. Any disagreements will be resolved by consensus.
Managing references
Bibliographic software (EndNote) (Thomson Reuters), will be used to manage retrieved references. MM will be responsible for identifying and removing duplicates, ordering and recording the receipt of any inter-library loans and obtaining the full-text papers. MM will be the sole team member responsible for adding or amending library records in EndNote.
Data extraction, procedures and data management
The EPOC data extraction form in combination with the EPOC data checklist (see Additional file 2) will be used to extract data from relevant studies. Two reviewers (MM and LT) will work independently to extract data. Disagreements between the two reviewers will be resolved by discussion and consensus, or resolved by a third author (MB). Data extraction will include study setting, study population and participant demographics and baseline characteristics, details of the intervention and control conditions, study methodology, recruitment and study completion rates, outcomes and times of measurement, indicators of acceptability to users, suggested mechanisms of intervention action, information for assessment of the risk of bias and variables related to study quality. Study authors will be contacted to request data missing on methods or results. Information on missing data and dropouts will be assessed for each study. We will report the number of participants included in the final analysis of each study as a proportion of all participants in the study. The possible effects of the missing data will be discussed. Data will be included only for those participants whose results are known.
Dealing with missing data
Study authors will be contacted to request data missing on methods or results. Information on missing data and dropouts will be assessed for each study. We will report the number of participants included in the final analysis of each study as a proportion of all participants in the study. The possible effects of the missing data will be discussed. Data will be included only for those participants whose results are known.
Quality assessment
We shall assess the quality of studies and assessment of bias using the Cochrane’s Collaboration tool for assessing risk of bias presented in Additional file 3[29]. Two researchers (MM and LT) will independently rate risk of bias of each study. Discrepancies will be resolved by discussion and consensus.
Data analysis
Measures of treatment effects
We shall summarise and describe the characteristics of the population, interventions and outcomes, using descriptive statistics. Standardised mean differences, Hedges g, and weighting studies using inverse of variance will be calculated for continuous outcomes. Risk ratios (RR) will be calculated and we shall use the Mantel-Haenszel method to combine studies. We shall report outcomes using 95% confidence intervals (CI), with random-effects models.
Assessment of reporting biases
Funnel plots will be drawn to investigate the relationship between study power and effect size. Possible reasons for any asymmetry will be discussed.
Data synthesis and assessment of heterogeneity
A meta-analysis of RCTs and quasi-experimental studies will be conducted using RevMan.
Statistical tests of heterogeneity (chi-square and I-square) will be carried out. A random-effects model will be used to allow for expected heterogeneity. Effect estimates will be weighted by the inverse of their variance, giving greater weight to larger trials.
Sub group analyses will be carried out for studies with similar research questions based on: a) type of interventions: group-based CBT; individual CBT and b) phase of illness: early onset psychosis vs. chronic.
Sensitivity analysis will be carried out to explore the effects of the addition or removal of lower quality studies.
We will use the GRADE system 11 [30] to assess confidence in the quality of evidence of individual outcomes and strength of recommendations.