My Son Had An Episode The Other Day And I'm

My son had an episode the other day and I'm not sure if it was drugs, and if so what I should look for. His eyes were blank, he slurred his words, kept repeating the same questions over and over, and said he doesn't remember most of the day and was very defiant. He says he took nothing and that it scared him. I think it must be drugs, but I'd like to know what I should look for and if a urine drug test or hair drug test would give me the best results. It was 3 days ago.