I take Zoloft, 100mg daily. I also have used up to nearly 2 bottles of robo max strength with mild sweating, and jittery-ness. Not sure if it's S.S. or what, but it never was a "problem".
Ingo_2001 is correct, most of the "anti-depressant" action caused by SSRI's are not direct, but indirect. Thus the reason it somtimes takes 2-6 weeks to see improvment. The same is coming off. After about a week off my zoloft (somtimes i forget), I get "brain shakes" which I thought were cool at first--i AM a drug user--
However, they are very scary when driving, or just trying to be "normal". They really are not somthing I would like to experiance again. If I come off the Zoloft anytime soon, im gradually stepping down my dosage over the span on like 8 weeks.
But to answer the original question--I think that SSRI's CAN most definatley cause S.S., but I think it all depends on the individual. Hell, some people are even deathly allergic to rec. doses of dxm...