Adler 1993.
| Methods | Allocation: "random allocation", ratio of 3 vitamin E: 2 placebo. Double‐blind: no further details. Duration: 36 weeks (preceded by 2 week washout). Setting: inpatients and outpatients of the Department of Veterans Affairs Medical Center, USA. Design: parallel group. | |
| Participants | Diagnosis: schizophrenia, depression (no criteria) and antipsychotic‐induced TD (Research Diagnostic Criteria, Schooler and Kane). N = 40*. Sex: 2 female, 27 male*. Age: average vitamin E 58.0 (SD 9.5) years; placebo 61.0 (SD 9.2) years* | |
| Interventions | 1. Vitamin E: dose increasing over 3 weeks to 1600 IU/day. N = 24.** 2. Placebo. N = 16.** Stable antipsychotic medication: dose average (CPE) vitamin E = 536 mg/day (SD 642); placebo = 921 mg/day (SD 1026). Compliance assessed by pill counts. | |
| Outcomes | TD symptoms: AIMS. Leaving the study early. | |
| Notes | * initial report at 8 weeks, N = 29.
** three people left the study in the first 2 weeks and could not be considered in the analysis ‐ original group assumed from 3:2 randomisation. Source of funding: Supported in part by the Department of Veterans Affairs. Declarations of interest: Not reported. |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | "Patients were randomly assigned to treatment with Vitamin E, 400IU, or one matching placebo capsule, by mouth, b.i.d." No further details |
| Allocation concealment (selection bias) | Unclear risk | "We used a randomization of 3:2 (vitamin E to placebo) to maximize the number of patients receiving active treatment while maintaining the blind". No further details |
| Blinding of participants and personnel (performance bias) | Unclear risk | "Both rater and patient were blind to the patient's drug assignment". No further details |
| Blinding of outcome assessment (detection bias) | Unclear risk | "Both rater and patient were blind to the patient's drug assignment". No further details |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | “One patient dropped out after 2 weeks due to non‐compliance” “Two patients developed significant medical illnesses ... unrelated to study treatment”, “By prior design, treatment for the first 8 patients was terminated after 8 weeks.” |
| Selective reporting (reporting bias) | Unclear risk | All expected outcomes have been reported but there is no study protocol to confirm that all planned outcomes were reported. |
| Other bias | Unclear risk | Baseline AIMS scores were somewhat higher in the vitamin E group than in the placebo group, however, this difference was not statistically significant. Small sample size |