Methods | Allocation: random, no further details. Blindness: double, identical capsules. Duration: 78 weeks. Design: parallel. Location: multicentre. |
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Participants | Diagnosis: (DSM-IV) schizophrenia, more than one schizophrenic episode, responder. N=1493. Age: 18-65 years (mean=40.6 years). Gender: 1080 M, 380 F. History: duration of illness not reported, age at onset not reported. Setting: in- and outpatient. |
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Interventions |
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Outcomes | Leaving the study early: any reason, adverse events, inefficacy. Global State: CGI-S Mental State: PANSS total score Service use: number of patients re-hospitalised. Death: suicide attempt. Adverse effects: open interviews, EPS (use of antiparkinson medication, akathisia), cardiac effects (ECG), prolactin-associated side-effects, sedation, weight gain, laboratory (prolactin, lipids, glucose) Unable to use- Withdrawal due to ’extrapyramidal effects’ (no usable data). |
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Notes | 33 patients were excluded before analysis. | |
Risk of bias | ||
Bias | Authors’ judgement | Support for judgement |
Random sequence generation (selection bias) | Unclear risk | Random, no further details. |
Allocation concealment (selection bias) | Unclear risk | No further details. |
Blinding (performance bias and detection bias) Subjective outcomes |
Unclear risk | Double, identical capsules. Whether blind-ing was successful has not been examined, but both compounds differ quite substantially in side-effects. This can be a problem for blinding |
Blinding (performance bias and detection bias) Objective outcomes |
Low risk | Objective outcomes such as laboratory measures or death are unlikely to have been much affected by problems of blinding |
Incomplete outcome data (attrition bias) All outcomes |
High risk | The attrition was extremely high (75%) , and it is unclear whether any statistical method can account for such a high dropout rate. Efficacy outcomes were evaluated based on mixed models analysis |
Selective reporting (reporting bias) | Low risk | No evidence for selective reporting. |
Other bias | Unclear risk | Dose ranges were quite different, the upper dose range of olanzapine was 30 mg whereas risperidone could only be titrated up to 6 mg /day. No wash-out period. An overlap in the administration of formerly given antipsychotics was permitted for the first four weeks after randomisation. Allocation to ziprasidone treatment was not possible from the start of the study because ziprasidone was only available at later stages |