I've been screwing around with syndromes a bit here, and I just want to share what I've figured out. I imagine a lot of it is common knowledge.
* If a syndrome is applied that shares the same SYN_IDENTIFIER token as a syndrome that already exists, the prior syndrome is applied again, ignoring, as far as I can tell, everything else about the new syndrome.
* If you have a syndrome with a start time after its end time, it won't have any effect, unless you reapply the syndrome, in which case the start time will not change, but the end time will change to (<end time> + <current phase>).
* If a syndrome has multiple effects, and one of the effects passes its start and end time while the syndrome itself is still active, reapplying the syndrome will NOT cause the end time to change. That component of the syndrome is effectively disabled. This can allow a form of "acquired immunity" to syndromes if the syndrome has a benign effect that never ends.
* Multiple effects of a syndrome are tracked separately, even if they have the same effect. This means you can't "cancel out" a syndrome; having a CE_ADD_TAG:CAN_SPEAK with one syndrome and CE_REMOVE_TAG:CAN_SPEAK just results no speaky.
I've been trying to figure out a means to remove a syndrome from an afflicted creature, but no dice. You can push forward the END timer, but you can't push it back, even though throwing negative numbers at the START and END times don't cause any errors, due to the fact that the components are independent.