Children growing up in former communist CEE countries during the 1980s were subjected to horrific amounts of industrial pollution, including extreme levels of prolonged lead exposure. Since lead is theorized to be a primary culprit in exacerbating violent crime, you would assume there would be a sizeable discrepancy in the homicide rate between, say, former East Germany and West Germany, or Western Europe and Eastern Europe as a whole. But the difference in the homicide/violent crime rate is negligible, with many former communist CEE countries having a lower homicide rate than Western Europe. I suspect the same is true when comparing the rate of mental disorders, which is another malady that is supposedly influenced by exposure to high levels of industrial pollution.
That is from commentator Aurel at SSC.