Meta-regression was performed in SPSS 19.0 using linear regression. Trials were weighted
using the generic inverse variance method. Effect size (SMD) of trials was entered as the dependent variable with the variables of interest being the independent variable. We used a meta-regression techniques to examine the association between omega-3 and naturally continuous variables such as (1) trial duration, (2) EPA dose and (3) DHA dose in omega-3 preparations. For our primary analysis examining the efficacy of omega-3 FAs for MDD we used a significance threshold of p