The wonderful thing about the Lord is that He doesn't need us to believe in Him --just because we don't believe doesn't mean He's not there! He doesn't need anything from us. So tell Donna she has nothing to lose by turning her depression over to Him just to see what happens. He will either help her or not. But either way, what does she have to lose by asking? Nothing--but she might just gain help by taking some of the weight off of her shoulders. He likely won't lift her out of it immediately (although it's possible), but He will lead her in the right direction.