Additional linear regression analyses indicated that this intercept difference resulted from significantly higher levels of alcohol units per week for participants in the control condition compared to those in the experimental condition at 1-month ( beta = -2.56 , SE 0.74 , Cohen 's d = 0.20 , P = .001 ) , 3-month ( beta = -1.76 , SE 0.60 , Cohen 's d = 0.13 , P = .003 ) , and 6-month ( beta = -1.21 , SE 0.58 , Cohen 's d = 0.09 , P = .04 ) follow-up intervals .