Motivational and emotional disorders (i.e. apathy and depression) are very frequent in dementia and might greatly affect the positive psychological state experienced during social HRI. We conducted a six-weeks study in two nursing homes comparing the affective states that two playful activities, board cognitive games and social robot play (Pleo), were able to elicit in people with dementia. Results show that a significant increase in pleasure (positive affect) is present in the robot condition when participants are considered in their totality, but once they are grouped based on the presence of motivational and emotional disorders, the pleasure experienced in the robot condition is significantly lower in the group with such disorders