Patient care about improving, they don't care about improving compared with placebo.
In many cases a good psychiatrist tests multiple drugs to find the one that works for the client. The point of going to a psychiatrist is also that it's believed that the psychiatrist doesn't give you a random antidepressant but one that fits your personal needs.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4172306/pdf/zfp_222_3_128.pdf
The background on this story is a community of science people found a bunch of unpublished studies that, when weighed with the studies which supported antidepressant approval, showed they were no more effective than placebo in mild-moderate cases.
Except unlike placebo, antidepressants express a wider range of severe side effects, like worsening depression and suicide.
Isn't this a scandal? How do psychiatrists still prescribe these en masse?