Drug testing of neurology residency applicants is recommended to increase protection for the public, but not all residency programs require a drug screen. If the interviewers ask this question, they are advising you of their pre-employment drug screen and ask if you'll pass, so they can decide if they want to continue with you in the interview process. Residency programs invest a lot of money in hiring residents, and they want to avoid sending you for a drug test if you will not pass.
As with any interview question, you want to focus on being completely honest in your response. As embarrassing as it may be, if you do not think you will pass the drug test, you must inform the interviewers now. If passing the drug test will not be an issue, ensure the interviewer that you will pass the test because you do not use drugs.
