There was a statistically significant advantage of CBI over IBI in substance-specific ASSIST scores for marijuana ( b = -1.73 ; 95 % CI = -2.91 , -0.55 ; Cohen 's d = 0.26 ; P = 0.004 ) and cocaine ( b = -4.48 ; 95 % CI = -8.26 , -0.71 ; Cohen 's d = 0.50 ; P = 0.021 ) at 3 months .