A: Before you do anything else, be absolutely certain that you're well advised on all up-to-date aspects of employment law. I'm not suggesting your decisions should be governed by inhuman adherence to someone else's guidelines; just that you don't want to be taken by surprise should this situation deteriorate further.
The fact that the first week's leave you granted her was unpaid seems a little mean to me. I would have thought that a valued employee, going through a deeply stressful time, and with or without a doctor's note, should not have been further penalised. Assuming that she is indeed a valued employee, and that you all want to see her fully recovered and back at work, she deserves a little more generosity. I'm fairly certain you'd see such generosity repaid.
I know it's a further demand on your time - but I believe you should go and see her at her home (phone first, obviously), talk things through and between you work out an agreed date of return. You'll learn a lot from your conversation - and your decision to visit should mean at least as much to her as the most understanding of words. If you sense she's well on the mend, don't be afraid to exert a little gentle pressure; she's probably a bit apprehensive about the act of re-entry and the comments of workmates.
Jeremy Bullmore is a former creative director and chairman of J Walter Thompson London. His book Another Bad Day at the Office? is published by Penguin at £6.99. Address your problem to Jeremy Bullmore at: firstname.lastname@example.org. Regrettably, no correspondence can be entered into.