ISI significantly improved more in eszopiclone ( mean = -10.7 , 95 % CI = -13.2 ; -8.2 ) than in placebo ( mean = -6.9 , 95 % CI = -9.5 ; -4.3 ) with a between-group difference of -3.8 ( 95 % CI = -7.5 ; -0.2 ) .