Methods
Criteria for considering studies for this review
Types of studies
All relevant randomised controlled trials (RCTs). We excluded quasi-randomised trials, such as those where allocation is undertaken on surname. If a trial was described as double-blind, but it was implied it had been randomised, we included these trials in a sensitivity analysis. We included randomised cross-over studies but only data up to the point of first cross-over because of the instability of the problem behaviours and the likely carry-over effects of all treatments.
As CBT requires the person to actively engage and participate in the therapy, it may not be possible to blind the participant to condition (that is, it may not be possible to provide a placebo control condition to reduce the effects of anticipated outcome on behalf of the participant). However, it is possible and desirable to blind the trialist to condition (that is, the trialist collecting outcome data is unaware of the allocation of the individual participant). Accordingly, single-blind trials are considered of appropriate methodological quality for the assessment of this type of intervention.
We compared the outcomes of trials that described a single-blind procedure with trials that did not describe any blinding procedure. If there was no substantive difference within primary outcomes (see Types of outcome measures) when these non-blinded studies were added, then we did not include them in the final analysis. If there was a substantive difference, we only used only single-blinded randomised trials and the results of the sensitivity analysis are described in the text.
Types of participants
People with a current diagnosis of schizophrenia, diagnosed by any criteria, irrespective of gender or race. We did not include participants who had very late onset of illness (onset after the age of 60 years) or those with other psychotic disorders such as bipolar affective disorder, substance-induced psychosis, significant physical or sensory difficulties or people with coexisting developmental disorders and/or learning disabilities. If studies randomised people with schizophrenia and those with the above disorders, we only included trials where more than 50% of the participants had a diagnosis of schizophrenia.
This review did not include trials that report outcomes from participants deemed to be "at-risk" of developing schizophrenia in the future.
Types of interventions
1. Cognitive behavioural therapy (CBT)
The label cognitive behavioural therapy has been applied to a variety of interventions, accordingly, is difficult to provide a single, unambiguous definition. Recognising this, the review authors constructed criteria that were felt to be both workable and to capture the elements of good practice in CBT.
In order to be classified as 'well-defined' the intervention must clearly demonstrate the following components:
a discrete psychological intervention, which is in addition to, and separate from, other therapeutic interventions (for example, behavioural family therapy) and
recipients establish links between their symptoms, thoughts and beliefs, and consequent distress or problem behaviour and
the re-evaluation of their perceptions, beliefs or reasoning relating to the target symptoms; this may include the re-evaluation of specific "inferential" beliefs or more global "evaluative" beliefs.
All therapies that did not meet these criteria (or that provided insufficient information) but were labelled as 'CBT' or 'Cognitive Therapy' were included as 'less-well-defined CBT'. We conducted a sensitivity analysis on the primary outcomes of this review (see Types of outcome measures) in order to investigate whether a 'well-defined' implementation of this therapy presents with differential outcomes.
In addition, we undertook a sensitivity analysis between studies that employed qualified CBT therapists compared with relatively unqualified CBT therapists. Qualified CBT therapists may be defined as:
persons possessing appropriate professional qualifications for the provision of CBT (e.g., British Association of Behavioural and Cognitive Psychotherapy (BABCP) accreditation, Diploma in CBT, or other professionally accredited qualifications involving CBT as major part of training (e.g. Clinical or Counselling Psychologist)) or
in situations where the qualifications of the therapist are unclear but they appear to have received training in CBT or specific training for the trial and there is a thorough adherence protocol.
Unqualified CBT therapists may be defined as persons not possessing appropriate professional qualifications or no report of training and adherence protocols.
2. Other psychosocial interventions
Where standard care has been supplemented by additional psychological or social interventions, or both, such as supportive therapy, psycho-education, family therapy and other 'talking therapies'.
This review distinguishes between trials that described 'active' psychosocial i
MethodsCriteria for considering studies for this reviewTypes of studiesAll relevant randomised controlled trials (RCTs). We excluded quasi-randomised trials, such as those where allocation is undertaken on surname. If a trial was described as double-blind, but it was implied it had been randomised, we included these trials in a sensitivity analysis. We included randomised cross-over studies but only data up to the point of first cross-over because of the instability of the problem behaviours and the likely carry-over effects of all treatments.As CBT requires the person to actively engage and participate in the therapy, it may not be possible to blind the participant to condition (that is, it may not be possible to provide a placebo control condition to reduce the effects of anticipated outcome on behalf of the participant). However, it is possible and desirable to blind the trialist to condition (that is, the trialist collecting outcome data is unaware of the allocation of the individual participant). Accordingly, single-blind trials are considered of appropriate methodological quality for the assessment of this type of intervention.We compared the outcomes of trials that described a single-blind procedure with trials that did not describe any blinding procedure. If there was no substantive difference within primary outcomes (see Types of outcome measures) when these non-blinded studies were added, then we did not include them in the final analysis. If there was a substantive difference, we only used only single-blinded randomised trials and the results of the sensitivity analysis are described in the text.Types of participantsPeople with a current diagnosis of schizophrenia, diagnosed by any criteria, irrespective of gender or race. We did not include participants who had very late onset of illness (onset after the age of 60 years) or those with other psychotic disorders such as bipolar affective disorder, substance-induced psychosis, significant physical or sensory difficulties or people with coexisting developmental disorders and/or learning disabilities. If studies randomised people with schizophrenia and those with the above disorders, we only included trials where more than 50% of the participants had a diagnosis of schizophrenia.This review did not include trials that report outcomes from participants deemed to be "at-risk" of developing schizophrenia in the future.Types of interventions1. Cognitive behavioural therapy (CBT)The label cognitive behavioural therapy has been applied to a variety of interventions, accordingly, is difficult to provide a single, unambiguous definition. Recognising this, the review authors constructed criteria that were felt to be both workable and to capture the elements of good practice in CBT.In order to be classified as 'well-defined' the intervention must clearly demonstrate the following components:
a discrete psychological intervention, which is in addition to, and separate from, other therapeutic interventions (for example, behavioural family therapy) and
recipients establish links between their symptoms, thoughts and beliefs, and consequent distress or problem behaviour and
the re-evaluation of their perceptions, beliefs or reasoning relating to the target symptoms; this may include the re-evaluation of specific "inferential" beliefs or more global "evaluative" beliefs.
All therapies that did not meet these criteria (or that provided insufficient information) but were labelled as 'CBT' or 'Cognitive Therapy' were included as 'less-well-defined CBT'. We conducted a sensitivity analysis on the primary outcomes of this review (see Types of outcome measures) in order to investigate whether a 'well-defined' implementation of this therapy presents with differential outcomes.
In addition, we undertook a sensitivity analysis between studies that employed qualified CBT therapists compared with relatively unqualified CBT therapists. Qualified CBT therapists may be defined as:
persons possessing appropriate professional qualifications for the provision of CBT (e.g., British Association of Behavioural and Cognitive Psychotherapy (BABCP) accreditation, Diploma in CBT, or other professionally accredited qualifications involving CBT as major part of training (e.g. Clinical or Counselling Psychologist)) or
in situations where the qualifications of the therapist are unclear but they appear to have received training in CBT or specific training for the trial and there is a thorough adherence protocol.
Unqualified CBT therapists may be defined as persons not possessing appropriate professional qualifications or no report of training and adherence protocols.
2. Other psychosocial interventions
Where standard care has been supplemented by additional psychological or social interventions, or both, such as supportive therapy, psycho-education, family therapy and other 'talking therapies'.
This review distinguishes between trials that described 'active' psychosocial i
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