She had beendrivenover theedgeby theseparationfrom herhusband.
Aseriesofprofessionalfailuresfinallydrovehim over theedge.
It was thelackofsleepthatdroveme over theedge.
Whenpeopleare under so muchstress, asimplething liketheircarbreakingdown canpushthem over theedge.
Theinfectionthatbringssomeone to A&E may be the thing thatpushesthem over theedge, health-wise.