The experimental SFBT condition ( n = 131 ) showed significantly greater improvement than the waiting list condition ( n = 132 ) in depressive symptoms at 9 weeks and 4.5 months on the CES-D , with a small between group effect size at 9 weeks ( d = 0.18 , 95 % CI -0.10 to 0.47 ) and a large effect size at 4.5 months ( d = 0.79 , 95 % CI 0.45-1 .08 ) .