Adjustment device for vehicle seat, in particular for adjusting the backrest angle

The adjusting unit (1) has an internally toothed outer gear, an externally toothed inner gear and a drive unit which rotates one of the gears relative to the other of the gears for comfort adjustment (C) against an adjustable resistance. The adjustable resistance is temporary reduced for a quick adjustment (D). An independent claim is also included for a method for adjusting a backrest of a vehicle seat with an adjusting unit.