DVLA medical exam....!?

They took license off me back in october because i was sectioned under mental health act in august. They said i needed period of 3 months stable which i have. I've currently reapplied and said i need to go to a medication examination. I doctor report that was sent to them mentioned i have taken an illicit drug in the past few months. How will this effect it? And will it show up in my urine?