Multivariable prediction of functional outcome after first-episode psychosis: a crossover validation approach in EUFEST and PSYSCAN by Slot, MIE, Urquijo Castro, MF, Winter - van Rossum, I, van Hell, HH, Dwyer, D, Dazzan, P, Maat, A, De Haan, L, Crespo-Facorro, B, Glenthøj, BY, Lawrie, SM, McDonald, C, Gruber, O, van Amelsvoort, T, Arango, C, Kircher, T, Nelson, B, Galderisi, S, Weiser, M, Sachs, G, Kirschner, M, Fleischhacker, WW, McGuire, P, Koutsouleris, N