Berk 2014.
| Study characteristics | ||
| Methods | Double‐blind randomised controlled trial | |
| Participants |
Diagnosis: DSM‐IV major depressive disorder; MADRS score ≥ 18
N: 269 Age:N‐Acetylcysteine group M = 29.9 (SD = 13.0); placebo group M = 50.5 (SD = 12.5) Sex:N‐Acetylcysteine group 84% female; placebo group 75% female Baseline depression severity:N‐Acetylcysteine group MADRS = 27.7 (SD = 5.8); placebo group MADRS = 28.1 (SD = 5.8) |
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| Interventions | 12 weeks of treatment N‐Acetylcysteine (N = 135), 2 x 500 mg capsules twice daily Placebo (N =134), 2 capsules twice daily dusted in N‐Acetylcysteine to ensure similar odour Concomitant treatment: yes, patients continued existing treatments for depression |
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| Outcomes | Montgomery Asberg Rating Scale ) (MADRS) Response rate (≥ 50% reduction in MADRS scores) Remission rate (MADRS score ≤ 7) Clinical Global Impression‐Improvement and Clinical Global Impression‐Severity HARS Global Assessment of Functioning SOFAS SLICE‐LIFE LIFE‐RIFT Q‐LES‐Q Adverse events |
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| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | No details given on randomisation procedure |
| Allocation concealment (selection bias) | Unclear risk | No details given on allocation concealment |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Quote: ''To facilitate double‐blinding, the trial medications (both N‐acetylcysteine and placebo) were dispensed in identical numbers and capsule formulations in sealed containers by the trial pharmacist. Furthermore, to mask the distinct smell of the N‐acetylcysteine preparation, the placebo capsules were dusted with a tiny amount of N‐acetylcysteine so that all capsules had a similar odour'' |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Study described as double‐blind, trial pharmacist dispensed medications but unlikely to have conducted outcome assessments, however this is unclear |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Study reports dropouts, state exclusion of patients from analysis based on no post‐baseline data |
| Selective reporting (reporting bias) | Unclear risk | Protocol available, unclear if all prespecified outcomes reported in published report |
| Other bias | Low risk | No other potential sources of bias identified |