At the 6-month assessment , the differences between the intervention and comparison condition were all significant and sizable and became more pronounced when compared with the 4 - to 5-week outcomes : Davidson Trauma Scale ( Cohen 's d = -0.74 , P < .001 ) , Beck Anxiety Inventory ( Cohen 's d = -0.627 , P = .001 ) , Beck Depression Inventory II ( Cohen 's d = -0.638 , P = .002 ) .