You chose this career for a reason. Consider your motivation to help people and your drive to learn new, innovative techniques. From where did that motivation come? Perhaps you have struggled with addiction in the past or helped a loved one through the stressful situation. The interviewer is interested in your motivation, which is often something that enables you to push through the challenges. As an addiction psychiatrist, you will be assisting others with their most difficult issues, so you need to have a strong motivation, and an innate desire to keep moving forward.