Answer: Alcohol, drugs and some medications
Step-by-step explanation:
The substances that increases the reaction time of brain are some drugs, medications and alcohol.
Reaction time can be defined as the time which is used to react after the stimuli.
Taking alcohol, drugs and medication increases this time and the people after the stimuli react very slowly. It takes more than the usual time to react to any situation.
The situation can be critical if it is driving or any other circumstances where the person needs to be more attentive.