No post-Chernobyl effect was seen in the U.S., which was presumably too far away for the radioactive atoms to reach in sufficiently high amounts, Scherb added.
"Caesium stays mobile for longer in organic soils, hence why England and Wales still have some post-Chernobyl restrictions in upland areas," he told BBC News.
Compared with a similar group of women who lived in Kiev when Chernobyl exploded, twice as many evacuees had post-traumatic stress disorder and major depression at both interviews.