The effects of using the PReDicT Test to guide the antidepressant treatment of depressed patients: study protocol for a randomised controlled trial by Kingslake, J, Dias, R, Dawson, G, Simon, J, Goodwin, G, Harmer, C, Morriss, R, Brown, S, Guo, B, Ruhe, H, Lever, A, Veltman, D, van Schaik, A, Deckert, J, Reif, A, Stablein, M, Menke, A, Gorwood, P, Voegeli, G, Perez, V, Browning, M