This intercept difference resulted from higher levels in this outcome for participants in the control condition relative to participants in the experimental condition at @-month ( beta = -@ , SE @ , Cohen 's d = @ , P = @ ) , @-month ( beta = -@ , SE @ , Cohen 's d = @ , P = @ ) , and @-month ( beta = -@ , SE @ , Cohen 's d = @ , P = @ ) follow-up intervals .