There was a radio play (from ~20-25 years ago), where this is more or less the plot. Scientists find a cure to violence and unleash it on the world. It was a c

There was a radio play (from ~20-25 years ago), where this is more or less the plot. Scientists find a cure to violence and unleash it on the world. It was a chemical that makes everyone friendly. But what they didn't figure out was that it also makes you really stupid. So the scientists avoid the rain (because that's what transmits it), but after a while they all give into being stupid.