Do drugs impact a person's reaction time?
Yes. But it depends on the type of drugs being used.
Among these known types of drugs (Cannabinoids, Opioids, Stimulants, Club Drugs, Dissociative Drugs, Hallucinogens, and Other Compounds), Cannabinoids can slow your reaction time, and Opioids can cause drowsiness (which can still be considered a slower response time).
Hope this helps! :-)
If you want to know more about these drugs, you may read more here: http://www.eschooltoday.com/drug-abuse-and-teens/types-and-effects-of-drugs.html