Rosen 2011.

Study characteristics
Patient sampling	Prospective, unclear whether consecutive or random sample.
Patient characteristics and setting	N included in study: 86. N in analysis: 78. Age: Mean age at testing, schizophrenia: 23 (SD 3.4), bipolar: 24 (SD 6.3). Gender: M 50, F 36. Ethnicity: White 5. Comorbid disorders: Not reported. Duration of symptoms: Not reported. Concurrent medications used: Not reported for all time points. At the 20‐year follow‐up, 65% (n = 38) of schizophrenia patients were on psychiatric medications as were 58% (n = 15) bipolar patients. Of these, 55% (n = 32) of schizophrenia patients were on antipsychotic medications compared with 23% (n = 6) of bipolar patients. Inclusion criteria: Patients with schizophrenia and bipolar. Exclusion criteria: Not reported. Study aim: Prevalence and severity of first‐rank symptoms (FRS) during an extended period of time in patients with schizophrenia and bipolar disorder with psychosis. Previous treatment for schizophrenia: 64% of the total sample had one or fewer previous hopitalisations. There was no significant difference between patients with schizophrenia and bipolar disorder in the number of previous admissions. Clinical setting: Not reported. Country: USA.
Index tests	Description of FRS used: At index hospitalisation, the following FRS were assessed: thought broadcasting, thought insertion, thought withdrawal, delusions of control, a voice keeping a running commentary, and voices conversing. We evaluated at index and at all 6 follow‐ups the 2 FRS in DSM‐IIIR/IV criterion A for schizophrenia, auditory hallucinations that consist of a voice keeping a running commentary and voices conversing. In addition, at each follow‐up, all 12 FRS were assessed. Professionals performing test: Not reported. Resolution of discrepancies: Not reported. How FRS used in study: Diagnosis and prognosis.
Target condition and reference standard(s)	Reference standard: Research Diagnostic Criteria (RDC)* diagnoses at index hospitalisation were based on structured clinical interviews including the Schedule for Affective Disorders and Schizophrenia, and/or the Schizophrenia State Inventory and collateral information. Target condition(s): Schizophrenia and bipolar. Professionals performing test: Not reported. Interviewers performing follow‐up evaluations were not informed of diagnosis or the results of previous follow‐up evaluations. Resolution of discrepancies: Not reported. Diagnostic inter‐rater reliability was kappa = 0.88.
Flow and timing	Study process: This research follows a sample of patients with psychotic and mood disorders who were evaluated at index hospitalisation and then prospectively followed at 6 evaluations subsequently for 20 years. Follow‐up evaluations occurred at 2, 4.5, 7.5, 10, 15, and 20 after index hospitalisation. All 86 patients were assessed at the 20‐year follow‐up. First‐rank symptoms were individually evaluated at index hospitalisation and at each subsequent follow‐up. The assessment of FRS was based on the Schedule for Affective Disorders and Schizophrenia. Research Diagnostic Criteria (RDC) diagnoses at index hospitalisation were based on structured clinical interviews including the Schedule for Affective Disorders and Schizophrenia, and/or the Schizophrenia State Inventory and collateral information. Interviewers performing follow‐up evaluations were not informed of diagnosis or the results of previous follow‐up evaluations. Follow‐up: 20 years. Exclusions: Not clearly reported. Data on FRS at the 20‐year follow‐up were available for 73% of the original sample assessed.
Comparative
Notes	All patients were evaluated as part of the Harrow Chicago Follow‐up study. *The RDC were used for diagnosis because they provide diagnostic criteria that are independent of FRS, allowing diagnostic analyses that have not been confounded by the use of FRS as an inclusion criterion for schizophrenia.
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Unclear
Was a case‐control design avoided?	No
Did the study avoid inappropriate exclusions?	Yes
		Unclear	High
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?	Yes
		Unclear	High
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Unclear
Were the reference standard results interpreted without knowledge of the results of the index tests?	Unclear
		Unclear	Unclear
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Unclear
Were all patients included in the analysis?	No
Did all patients receive a reference standard?	Unclear
Did all patients receive the same reference standard?	Yes
Did all patients receive an index test?	Unclear
Did all patients receive the same index test?	Yes
		Unclear