2×2 Factorial Randomised Controlled Trial

The 2×2 factorial design improves statistical efficiency by enabling estimation of multiple effects within a smaller sample. Outcome assessors and statistical analysts are blinded, but participant blinding is not feasible given the nature of the interventions. Outcomes are assessed at three time points: baseline, end of the 6-week intervention, and 4-month follow-up. The trial enrols 120 participants allocated equally into four groups of 30. The 2×2 factorial design allows simultaneous estimation of the main effect of acupuncture, the main effect of MBSR, and their interaction effect. Block randomisation uses alternating block sizes of 6 and 8, with allocation concealment via sequentially numbered opaque sealed envelopes.