It should be generated by the Y List desk at APC. It won't comment on your performance and functions primarily as a space filler so that should you appear on the board, they know you spent time on the Y List and can take that into account. However, if you are using your time on the Y List constructively (say, to do a correspondence course, work on your IT skills or rebuild your fitness within the limits of your medical state) then you should make sure that APC knows this and includes it in your CR. Likewise, you may have had time to reconsider your career path and be considering a future in a trg centre or be desperate to return to an operational unit. Either way, make sure they know this as they will still have to recommend you for future employment and include your preferences for your next posting once your time on the sick is over.
does being on y list drastically effect my career?
Drastically, probably not. Not in any way that could be construed as "unfair", anyway. In some cases, it may act to your advantage, especially if you were in a particularly strong peer group before going onto the Y List. Relax. Enjoy the time at home while it lasts. Make the most of it, professionally. We'll have you back to work before you know it.