They're measuring a change in -- self reported -- symptoms to evaluate a medicine's usefulness. If SSRIs primary function is increasing indifference, a persona

They're measuring a change in -- self reported -- symptoms to evaluate a medicine's usefulness. If SSRIs primary function is increasing indifference, a personality inventory on sadness will still turn up as improved if the patient cares less about it. Saying that this is a treatment of the symptom is confounding effects and could pave the way for decades of poor science. And that's assuming that the data is interpretable in the way that they think it is and that it's not more akin to fMRIs.