To get this achievement in the first try, remember:
1. You can only use Doctor.
2. Use an Addon that increase the Madness rate. (gray or yellow)
3. Locate a survivor and stick with him, keep shocking (about 6-9 times) and get a distance and see if the survivor is placing his hands in their heads (you will be able to see him, even through walls), if he is, you can attack him just for fun or go to the other.
3.5 With the doctor you will be able to choose Shock Terapy or the Mace option (i don't recall the names, but you will soon understand), shock is awesome tracker but mace makes you run faster, in a chase, keep swaping those 2 options, to get it faster.
4. After shocking 2 or 3 survivors in their madness, hook one and let them scape.. the shock will spread easily to the others
Hint: even tho hooking make it easier, remember to don't kill them by hooking too fast, only if you are 100% sure they got max stage of madness.
ProTip: even if you didn't get the chance to trap one to the max stage, be cool and do not go in the gates, stay in a safe distance where the survivors will feel safe, and then start spreading shocks, probably one of them might test you, do not hit with the weapon, keep the shock and they will keep annoying walking around, between the gate and you...
ps: sorry my english