I am unfortunately a bit of "miracle" case as they had the gall to call it when I woke up in the hospital.
In my larger attempts over past few years, I've taken triple the lethal dose of lamictal (lamotrigine) and double the lethal dose of wellbutrin (bupropion). Put myself in a coma, stopped my heart a few times, the whole shebang. I've also gone the slow route and refrained from water and food for a week or so before getting caught. I was not excepted to survive the overdoses.
Part of what messed me up with the medications was, as I'm sure most people are aware, taking hundreds of pills will cause you to throw up no matter the medication. Had I kept down all of the lamictal I might have been able to succeed. Or maybe not. It was certainly the attempt that caused the most brain damage though; they first thought I wouldn't wake up, then they thougt I may be unable to relearn to walk after.
With the wellbutrin, what I hadn't accounted for was how severe the seizures would be and how much noise it would make. I had restrained my limbs and secured myself to a heavy piece of furniture in hopes of mitigating the issue, but that was not nearly enough. I broke many things in my unconscious struggle, and the cops were called by those who overheard.
With my overdoses being as lethal as they were, they kept me on constant watch and observation after the hospital and wards. Social workers, "peer support" people, therapists, psychs. I was not allowed to have any large quantities of medication, I will never be able to own or purchase or use a gun (even at a shooting range), I can't show any signs of distress or they'll lock me up me again, ect. Merciful options are few and far between these days.
As for locked wards, I've been in 7 of them at least. It's one thing to be abused by people normally. It's another to be abused in a place where you cannot escape it, held against your will and then they have the nerve to call it help and charge you for it at the end. Because who wouldn't want to live after being threatened, ripped from their home/life, forcibly drugged, and put into medical debt? I'm cured. :)
That being said I've met plenty of people who don't regret going to them, even viewing them as saving them. Guess it comes down to the place and if the person actually wants to be "helped", I guess.
I dunno. TLDR; Gotta pick something one can't be caught with even when unconscious I suppose, or something that acts quickly if being found is inevitable.