There is a field sobriety test for other substances besides alcohol. The problem with it is there is not a secondary test such as the intocxilyzer 8000 to test for a person being intoxicated. Also only about less than .05 % of Dui officers are able to do the other substances field sobriety tests. The other thing is the only way to find out if someone is intoxicated by another substance is to pee or blood test. Which you can only get through consent or warrant with no consequences for refusing. Also as backed up as the crime lab is. It will take longer for the results to come back.