Dear Amy: We are at loss as how to deal with our 17-year-old son (an only child). He has always pushed the boundaries. Teachers have long identified him as bright but unmotivated. But recently his behavior has gotten much worse. He usually makes it to school. He has a part-time food service job, but other than that he spends most of his time in his room with the door locked. He frequently argues with us, refuses to help at home, and needs multiple prompts to get to school or work.