troubled = confused, worried, anxious The troubled boy was scared. troublesome = describes a thing/person that makes you troubled The troublesome teacher made the boy feel troubled. troubling = describes an event that makes your troubled The troubling earthquake made a lot of people homeless.

Calvin's answer is correct, but possibly a little limited, as the words do not only relate to people. 'Troubled' can be a bit more generally 'subject to trouble', e.g. 'The project has been regularly troubled by delays'. 'Pomgolia's economy has been troubled since the recent poll result'. Similarly 'troublesome' is not limited to people - 'The cheap components used in the machines have been troublesome'.