HTR4 and major depressive disorder: More specifically, the objectives are (1) To investigate associations between 5-HT4R binding in the striatum and self-reported sexual function in the depressed state, (2) To determine if striatal 5-HT4R binding is specifically related to sexual desire and (3) In an exploratory analysis, in women only, to map if sexual desire can predict treatment outcome in depression after eight weeks of treatment, since a main scope of the NeuroPharm trial was to evaluate potential markers of treatment response.