Ihara 2009.

Study characteristics
Patient sampling	Prospective and consecutive.
Patient characteristics and setting	N included in the study: 626. N included in the analysis: 426. Age: Mean 30.9 (SD 10.9), range 16‐64. Gender: M 251, F 175. Ethnicity: Black 46.2% (n = 197); White British 53.8% (n = 229). Comorbid disorders: Not reported. Duration of symptoms: Not reported. Concurrent medications used: Not reported. Inclusion criteria: Age 16–64 years, resident within the 3 study areas (South East London, and Nottingham, Bristol), presence of hallucinations, delusions, thought disorder, bizarre or disturbed behavior, negative syndrome, mania or clinical suspicion of psychosis. Exclusion criteria: organic medical cause, or profound learning disability, previous contact with psychiatric services for psychotic symptoms. Study aim: To examine the prevalence of FRSs in a sample of first‐episode psychoses stratified by relevant demographic variable. Previous treatment for schizophrenia: None. Clinical setting: Inpatients and outpatients. Country: UK.
Index tests	Description of FRS used: FRSs were assessed within a month after first contact with psychiatric services. FRSs were assessed by SCAN (refers to the previous 4 weeks) and IGC case notes. SCAN incorporates the Present State Examination Version 10.0, which captures FRSs. "For persons for whom SCAN data were not obtained, FRSs as well as passivity experiences were judged by whether item IG26 (delusion of control) in the IGC was positive or not, as other categories in the IGC like IG25 contain mixtures of FRSs". Professionals performing test: Certified psychiatrists or psychologists*. Resolution of discrepancies: Not Reported. How FRS used in study: Diagnosis.
Target condition and reference standard(s)	Reference standard: Consensus diagnoses were made according to DSM‐IV and ICD‐10, using information obtained from the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) version 2.0 or the SCAN Item Group Checklist (IGC), which is scored from case notes. Target condition(s): All psychoses, schizophrenia, affective psychoses, non‐affective psychoses other than schizophrenia, and substance‐induced psychoses. Professionals performing test: Certified psychiatrists or psychologists* carried out the SCAN interviews and IGC scoring. A panel of clinicians received clinical information from the researcher who conducted the individual assessments and made a consensus diagnosis according to DSM‐IV and ICD‐10. Resolution of discrepancies: Not reported. "The inter‐rater reliability between the individual diagnosticians who were involved in the consensus diagnosis groups was good", no kappa score reported.
Flow and timing	Study process: People presenting with their first psychosis at health centres over 2 years were screened for inclusion. Psychopathology was assessed using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) version 2.0 or the SCAN Item Group Checklist (IGC), which is scored from case notes. FRSs were assessed within a month after first contact with psychiatric services using the SCAN and ICG case notes and SCAN refers to the previous 4 weeks. Consensius diagnoses were made according to DSM‐IV and ICD‐10 from the clinical information. Follow‐up: not reported.
Comparative
Notes	*Certified psychiatrists or psychologists who were trained in SCAN interviews at the Nottingham WHO training centre and had achieved acceptable item‐level agreement before certification. They also carried out the IGC scoring.
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	Yes
		Low	Low
DOMAIN 2: Index Test All tests
Were the index test results interpreted without knowledge of the results of the reference standard?	Unclear
Did the study pre‐specify whether they were using one or multiple FRSs?	No
		Unclear	Low
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Unclear
		Unclear	Low
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Yes
Were all patients included in the analysis?	No
Did all patients receive a reference standard?	No
Did all patients receive the same reference standard?	Yes
Did all patients receive an index test?	No
Did all patients receive the same index test?	Yes
		Unclear