The invention relates to a lighting system (100) and a method for controlling lighting conditions in a room (R). The lighting system (100) comprises a controller (101) for controlling internal light sources (121, 122) and at least one actuator (131, 141) for changing the amount of external light entering the room (R). Moreover, at least one sensor (111,112, 31,141) is provided for detecting a parameter relating to the actual or to a desired lighting level of the room (R). Thus it is possible to control the lighting of the room (R) according to a predetermined schedule, particularly with a circadian rhythm that can reduce delirium in a patient (P). The actuator may for example comprise means (141) for closing or opening curtains (142) in front of a window (W).
