An electric motor driven adjustable mattress has a shared casing in which a flat cushion element of a cushion structure and an electric motor driven adjustable support apparatus for supporting the cushion element are accommodated. The support apparatus has two or more support parts that are adjustable relative to one another, and that on their sides facing the cushion element are provided with spring elements for elastically resiliently supporting the cushion element. The support part, in addition to the spring elements situated on the side facing the cushion element, is also provided with further spring elements on the side facing away from the cushion element, so that the support apparatus is provided at least in sections, with spring elements on both sides along its longitudinal extension.