They haven’t been used as synonyms for decades. They describe two different things, believed to have two different origins:
Hi Lurk:
Thanks for the references re: differences between sociopaths and psychopaths.
In many, many contexts, however, the two terms are used, perhaps imprecisely, interchangeably. See, for example, the first sentence to the sixth paragraph of your original site, which states unequivocally that they are the same.
Looks like some newer smarter psychiatrists have divined a distinction.
So, to be safe, I’ll stay away from both personality types.
I have used sociopath and psychopath tests for fun and it gives me clear idea example is below
http://illnessquiz.com/sociopath-test/