Medicine has taken over my entire field of vision. I can't look at my girlfriend's forearms without thinking how easy and satisfying it would be to gently slip a cannula into her prominent, lovely veins. When we kiss, I'm feeling up her spine and assessing where I could best insert a lumbar puncture needle. I've managed to cut down on calling the ward from my mobile after work, but I can't stop making diagnoses on the bus.

You will be relieved to hear that we have all been washing our hands with unswerving diligence, which is more than I can say for some of our patients, one of whom I interrupted this morning urinating in his NHS water jug because his bottle was full. People on the cusp of dependence, I suspect, don't like asking for help, and I can see a lot of myself in some of the things they do. Which is why I felt particularly awkward on his behalf when the consultant came back from answering a call and poured him out a glass of water, explaining that he has to keep drinking if we're ever going to take his drip down. Needless to say we (the patient and I) kept our traps shut.

Death and disease continue unabated, but self-inflicted suffering seems to be all the rage among the patients coming my way in the casualty department this month. Teenage suicide attempts are always a treat, because (like deep vein thromboses) they're quick to manage and a good way to keep your numbers up in A&E. There's nothing like a reputation for ploughing through patients and clearing the waiting list in the run up to the Christmas rush.

Junkies, on the other hand, are a different story. First of all, let me put my cards on the table. As a Guardian-reading liberal wet, I tend to believe that heroin addicts are victims of society, and that their victimisation is counter-productive, the source of most of their problems, and emblematic of our victimisation of the morally weak in society in general.

Which is all very well until they steal my video recorder, or pitch up in casualty at one in the morning covered in vomit. Opiate overdoses, in the textbook, are very easy to manage: you get intra-venous access and hit them with an antidote called naloxone, which I am tempted to suggest should be handed out at needle exchanges to save us all the worry.

Now I don't know if you've ever looked at the arms of your average junkie, but by the time they get in deep enough to overdose, they have usually knocked off every vein in their body. The company they keep tends to be friendly to the point of total social disinhibition, and companions are over-eager to get involved in the workings of the casualty department. It's a shame that it would be frowned upon to ask for their help getting into a vein, because I imagine that they would be far better at it than me.

The other thing that textbooks tend not to mention about giving naloxone is that the moment it kicks in, the patient kicks out and sits bolt upright, bright-eyed and bushy-tailed, demanding to know what the fuck you think you are doing, wasting £10-worth of prime smack he worked really rather hard for, and shouts his head off for half an hour. Then, just when you are about to get away, the antidote wears off, they slip back into respiratory arrest, and start trying to choke on their own vomit again. This is no fun at all.

But the worst thing is that people just keep on trying to die on me, against the best efforts of everyone around them. So on Thursday night I had yet another family trying to blackmail me into shoving tubes in to feed their dying matriarch who, despite speaking not a word of English, was very clearly both well-oriented and determined to pass away peacefully (and thank God it was a week night so I could safely leave the decision for her own team to make the next morning).

And this morning, a man who I had looked after for three weeks, who I had caught laughing at the papers every morning ("It's all just a load of nonsense, I'm so glad I'm leaving it all behind"), who sat me down the first time we met in A&E and somehow made me share all my aspirations with him before telling me that I had it all wrong, that the most important thing in life was the person you chose to spend it with, and that when his wife of 53 years passed away he knew he was going to follow her soon . . . this morning he finally willed himself to death.