I really hate sectioning people. "No, please don't. Please? I just want to go home and be with my daughter." Oh Christ, when people beg and plead. I've not got the stomach for being a jailer. Now I don't want to present this as a horror story. It is definitely the right thing to do: this girl is horribly vulnerable to exploitation, and there are candidates lining up for the job out there who are well documented in the notes. And she only wants to go home because of some awful delusion about what is going to happen to her on the ward. But however I sell it to myself, there is still an innocent-looking girl in front of me who is terrified, and she is terrified of what I'm going to do to her. This is not a junior doctor feel-good moment.

I sit down, tired and wired by the whole experience, fill out the form in a hurry, and hand it to the nurse in charge. He sniggers. "According to this form, in your professional opinion you have grounds to detain Dr Michael Foxton under section 5(2) of the Mental Health Act 1983." Sectioning myself, in many ways, would be the neatest way out of this ugly episode. I tear the form up in a hurry and write out another one. There can't be many junior doctors on call who haven't at least toyed with the idea of admitting themselves, for a bit of a rest.

Then I think: I know what I would want, if I was this deluded and frightened and vulnerable. I would want to be sectioned. Hands down, no question about it. And the drugs, too, however imperfect they might be. Although I might want a veto on a couple. I would even have ECT as a last resort, honestly: because I know it is safe and I have seen it work.

Right. Look. There are three reasons to section somebody: risk to self, risk to others and risk of deterioration. If one day I am scared and confused and a danger to others - which this girl isn't, by the way - then obviously society is going to want to do something about it, and a nosy psychiatrist on a grotty ward is a marginally kinder and more appropriate parallel system than the norm for dangerous stuff, which is PC Plod and his grotty cell. And if I was in serious danger of killing myself, then God knows I would want someone to put me somewhere safe and watch me like a hawk so that I could live to see another day when the clouds had passed.

Perhaps you feel strongly about this: you are of absolutely sound mind right now (although take nothing for granted and be nice to the afflicted, because madness waits for us all). Perhaps, looking at the facts, you know that you would not want to be on a ward or on drugs in any circumstances. You would rather take your chances in that prison cell, or maybe restrained instead of sedated like in America, or maybe you want to see how things go in your afterlife. And you know you definitely don't want ECT.

So make a living will. It is probably my only good idea ever. I mean, mental illness of one kind or another has a lifetime incidence of well over 10%: it is a hell of a lot more likely than your video recorder breaking down within three years. I can promise you it is a much better use of your time and money than that pricy extended warranty. This is, after all, your life we are talking about. You could maybe even mention how you feel about organ donation and being in a coma while you are at it, and save your family a whole lot of fretting.

After all, sometimes it feels like all I do at parties is hold seminars defending the work of evil old psychiatry. People seem to cleave into either feckless buffoons who believe any infringement of liberties by a shrink is an act of patriarchal self-aggrandisement, or those, usually with a palpable fear of their own madness, who want to know why on earth "these people" are left to roam the streets lowering property prices. "Shouldn't you be looking after them?" they ask, as I think of three good reasons to pour my drink over their heads.

Patients are nice people, like everyone else, and so are psychiatrists. We are doing our best, and we are probably doing the right thing, but Christ it feels grim sometimes. If you feel so strongly about it either way, make a decision, make a living will, and try to get someone to take it seriously. And then maybe I can sleep easier in my bed, without that pleading, tearful face in front of my eyes.