A torsional vibration damper includes a drive-side transmission element connected to a drive and a takeoff-side transmission element, which can deflect rotationally with respect to the drive-side element. A damping device is installed between the two transmission elements and transmits torque between the drive-side transmission element and the takeoff-side transmission element. The damping device has a gas spring system with a reservoir containing a gaseous medium. The reservoir of the gas spring system is connected to a pressure circuit which allows, at least when there is a change in the torque to be transmitted by the gas spring system, adjustment of pressure in the reservoir to adapt the characteristic of the gas spring system to a new torque.