The aims of this review were to systematically identify the current evidence base of placebo (or “sham”) randomised controlled trials (RCTs) of spinal cord stimulation (SCS) for neuropathic pain and to undertake a meta-analysis to investigate the effectiveness of SCS when compared with a placebo comparator arm. Electronic databases were searched from inception until January 2019 for RCTs of SCS using a placebo/sham control. Searches identified 8 eligible placebo-controlled randomised trials of SCS for neuropathic pain. Meta-analysis shows a statistically significant reduction in pain intensity during the active stimulation treatment periods compared with the control treatment periods, pooled mean difference −1.15 (95% confidence interval −1.75 to −0.55, P = 0.001) on a 10-point scale. Exploratory study–level subgroup analysis suggests a larger treatment effect in RCTs using a placebo control (defined as studies where the device was inactive and at least one of the study procedures was different between the arms) than a sham control (defined as all study procedures being equal between arms including SCS device behaviour). Our findings demonstrate limited evidence that SCS is effective in reducing pain intensity when compared with a placebo intervention. Our analyses suggest that the magnitude of treatment effect varies across trials and, in part, depends on the quality of patient blinding and minimisation of carryover effects. Improved reporting and further methodological research is needed into placebo and blinding approaches in SCS trials. Furthermore, we introduce a differentiation between placebo and sham concepts that may be generalisable to trials evaluating surgical or medical procedures.

Objective: To perform a network meta‐analysis (NMA) to compare the long‐term effectiveness of mindfulness‐based cognitive therapy (MBCT) with available strategies for prevention and time to depressive relapse.Methods: Seven electronic databases were searched up to June 2019. Studies evaluated MBCT for the management of depression‐related outcomes and follow‐up assessments occurred at 12 months or longer.Results: Twenty‐three publications were included, 17 of which were randomised controlled trials (RCTs). Data from 14 RCTs including 2077 participants contributed to meta‐analysis (MA) and NMA to assess relapse of depression and 13 RCTs with 2017 participants contributed to MA and NMA for time to relapse of depression. NMAs showed statistically significant advantages for MBCT over treatment as usual (TAU) for relapse of depression (RR = 0.73, 95% CI 0.54 to 0.98) and for MBCT over TAU and placebo for time to relapse of depression (MBCT vs TAU: HR = 0.57, 95% CI 0.37 to 0.88; MBCT vs placebo: HR = 0.23, 95% CI 0.08 to 0.67). Subgroup meta‐analysis of relapse of depression by previous number of depressive episodes showed similar results between subgroups. Subgroup meta‐analysis by the use or not of booster sessions suggests these may lead to improved effectiveness.Conclusions: MBCT is more effective than TAU in the long‐term in preventing relapse of depression and has statistically significant advantages over TAU and placebo for time to relapse of depression. No statistically significant differences were observed between MBCT and active treatment strategies for rate of relapse or time to relapse of depression.