Abstract: Embodiments disclosed herein relate to polycrystalline diamond compacts (“PDCs”) including at least one mechanically-stressed polycrystalline diamond (“PCD”) table having an upper surface that exhibits a compressive stress state. Providing a selected support structure to the mechanically-stressed PCD table and/or generating a favorable stress state in the upper surface of the mechanically-stressed PCD table may improve a toughness and/or a strength of the mechanically-stressed PCD table and the PDC. In an embodiment, a PDC includes a substrate including an interfacial surface and a preformed PCD table attached to the substrate. The preformed PCD table includes an upper surface spaced from a bottom surface that faces the interfacial surface of the substrate. In such an embodiment, the upper surface of the preformed PCD table exhibits a mechanical deflection and a concave curvature induced by deflecting the preformed PCD table toward the substrate.