Help with drug baseMoodEffect

[Soggy Noodle]

So I am adding in drug A but instead of having a hardcode +5 or -5 i want to add a chance to it. so that upon taking the drug A there will be a 50/50 chance to either have a positive or negative effect on your pawns mood. But i can't seem to figure out where to add this in. any help or links will be appreciated.