While multivariate analyses confirmed that randomization to collaborative care was associated with greater improvement in mood symptoms ( odds ratio [ OR ] = 3.1 ; 95 % - confidence interval [ CI ] = 1.8-5 .4 , p < 0.0001 ) and mental HRQoL ( OR = 3.6 , CI = 1.4-9 .3 , p = 0.01 ) , use of antidepressant medication had no differential impact on either measure ( p = 0.06 and p = 0.92 , respectively ) .