Several effects not involving lifetime MDD status emerged. Results indicated that main effects of reference (F(3, 906) = 122.3, p < .001) and channel (F(3, 906) = 39.2, p < .001) were qualified by a reference by channel interaction (F(9, 2718) = 5.8, p < .001), and supplemental mixed models for each reference separately indicated that main effects of channel emerged for AVG, CSD, and LM (all p < .001) but not Cz (p > .09). For AVG and LM, F2-F1 was associated with the largest relative left frontal activity, followed by F4-F3, F6-F5, then F8-F7 (all channels were significantly different from each other at p < .05 with the exception of F2-F1 and F4-F3 for AVG). For CSD, F2-F1 and F4-F3 were associated with higher relative left frontal activity than F6-F5 and F8-F7 (all p < .05) but frontal asymmetry did not differ within medial channels (F2-F1 and F4-F3) or within lateral channels (F6-F5 and F8-F7).
