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. 2020 Jul 3;2020(7):CD009533. doi: 10.1002/14651858.CD009533.pub2

Wykes 2007.

Study characteristics
Methods Allocation: randomised.
Blinding: single‐blind.
Duration: 6 weeks and 26 weeks assessment.
Setting: inpatient, UK.
Participants Diagnosis: schizophrenia (DSM‐IV)
N = 40
Age: Mean 18.2 years, range 14‐22 years
Sex: M 26, F 14
History: diagnosis of schizophrenia with onset of illness prior to 19 years and duration of illness less than 3 years, cognitive difficulties, cognitive flexibility, difficulties in social functioning (as evidenced by at least one problem on the Social Behaviour schedule), on stable dose and type of medication for the last one month
Exclusion criteria: Organic brain disorder e.g. epilepsy, IQ < 65, diagnosis of substance abuse as defined by DSM‐IV, plan to change medication during the trial
Interventions 1. PI: Cognitive Remediation Therapy
Thrice a week 40 hourly sessions of CRT. Participants also continued their previous treatment. N = 21
2. Control: treatment‐as‐usual. N = 19
Outcomes Cognitive functioning: WCST, Digit span, Modified Six Elements Test
Leaving the study early
Unable to use:
Global state: Social Behaviour Schedule (SBS), Rosenberg Self‐Esteem Scale (no usable data reported)
Mental state: BPRS (no endpoint mean or SD given)
Quality of life: QoLS (no usable data reported)
Notes Funding: most of this project was supported by a grant from the Mental Health Foundation to Prof. Wykes and Prof. S. Frangou.
Conflict of interest: Not reported.
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) High risk Quote: "Block randomisation was used with CRT and control treatment being assigned randomly to 4 patients each within blocks of 8".
Response: The exact method of random sequence generation has not been described in the paper.
Allocation concealment (selection bias) Unclear risk Details of the methods followed by the researcher in order to maintain allocation concealment were not described in the paper.
Blinding of participants and personnel (performance bias)
All outcomes High risk Quote: "Participants were recruited from those in contact with mental health services in south London usually while they were in‐patients."
Response: Participants received the experimental interventions and control arm received only treatment‐as‐usual. Partcipants and other members of the treatment team were not blind and there were obvious differences in the psychological interventions versus treatment‐as‐usual, which has a risk of introducing bias.
Blinding of outcome assessment (detection bias)
All outcomes Low risk Quote: "Symptom and quality of life assessments were assessed by an independent rater who was blind to group allocation. Self‐report assessments (cognition and self‐esteem) and informant ratings (social behaviour) were collected by a research assistant who was not blind to group allocation."
Response: The cognitive outcomes, self esteem, social behaviour ratings were assessed by raters who were not blind to the allocation status. The outcome assessors for symptoms and quality of life were blind to the intervention received by the participants as described in the paper.
Incomplete outcome data (attrition bias)
All outcomes Low risk Quote" "Analyses were based on an intention to treat, i.e. participants were analysed in the treatment group to which they were randomised irrespective of whether they adhered to their treatment."
Reason: Intention‐to‐treat analysis was conducted and a study flow diagram is reported by the authors.
Selective reporting (reporting bias) High risk Clear outcome scores were not reported for many of the outcome measures. Interaction analysis was done and reported for several variables.
Other bias Unclear risk None reported.

BPRS: Brief Psychiatric Rating Scale
BMT: Bckward Masking Task
CACR: Computer Assisted Cognitive Remediation Programme
CBCL: Child Behaviour Checklist 
CG: Computer Games
CGAS: Childrens Global Assessment Scale
COWAT: Controlled Oral Word Association Test
CPT: Continuous Performance Test
CRP: Cognitive Remediation Programme
CRT: Cognitive Remediation Therapy
DSM‐IV(‐TR): Diagnostic and Statistical Manual of Mental Disorders ‐ 4th edition (‐Text Revision)
HoNOSCA: Health of the Nation Outcome Scales for Children and Adolescents
ICD‐10: International Statistical Classification of Diseases and Related Health Problems‐10th Revision
IQ: Intelligent Quotient
ITT: Intention to Treat
NOS: Not Otherwise Specified
PANSS: Positive and Negative Symptom Scale
PE: Psychoeducation
PedsQL: Pediatric Quality of Life Scale
PI: Psychological Interventions
PTP: Psychoeducational Treatment Programme
QoLS: Quality of Life Scale
RAVLT: Rey Auditory Verbal Learning Test
RBANS: Repeatable Battery for Assessment of Neuropsychological States
SBS: Social Behaviour Schedule
SCCS: Self consistency and congruence scale
SIPS: Structured Interview for Prodromal Symptoms
SOPS: Scale of Prodromal Symptoms
SPAN‐12: Span of Apprehension Task
TAU: Treatment As Usual
TMT‐B: Trail Making Test B
VABS: Vineland Adaptive Behavioural Scales
WCST: Wisconson Card Sorting Test
WISC‐IV: Wisconson Card Sorting Test, 4th Edition
WMS‐III: Wechsler Memory Scales, 3rd edition