Induced theta ERS also showed a significant main effect of group (F(2, 143) = 14.01, P < 0.001, ηp2 = 0.16). Tukey's HSD revealed that all pairwise differences among group means were significant (all P < 0.03). These results show (1) that theta ERS was larger in both STAA and LTAA compared with controls (Cohen's d = 1.13 and 0.50, respectively) and (2) the magnitude of this enhancement (vs. controls) was greater in STAA than in LTAA (i.e., the theta ERS effect was smaller as a function of length of abstinence; d = 0.64). ITC values were very low (mean ITC ± SE: NAC: 0.078 ± 0.003, STAA: 0.079 ± 0.004, LTAA: 0.088 ± 0.004), indicating that the induced theta activity was not consistently phase locked to the stimulus, and did not differ between groups (F(2, 143) = 2.63, P = 0.08).
