When you have AS, you don’t process information the same as other people. We have rigid, systematic ways of thinking that give us excellent rote memory, but that hinder our ability to combine different pieces of data to create a larger whole or easily shift from one thought sequence to another. Sounds complex? Let me explain.

If you imagine each sensory input, thought or piece of knowledge as a sheet of paper, and the autistic brain as a giant filing cabinet, it goes some way to understanding how we operate. Every sheet of paper needs to be analysed, categorised, related to other sheets of paper and then filed in its relevant folder in the relevant drawer before we are done with it. It seems great in theory, but in practice? Bloody exhausting.

Processing information in this manner takes both time and huge expenditure of mental energy. Sometimes people with AS can seem a little slow when you’re talking to them, but they’re not – they’re just busily interpreting all those little nuances of social interaction that neurotypicals do automatically. Sometimes you can say something to an Aspie, and it’ll be minutes, hours or even days before they get back to you, because that’s how long it can take to work through everything you’ve said, figure out what it all means, and create an appropriate response. And if you give me a list of instructions, you can bet your bottom dollar that I’ll focus so intently on the first step to make sure I understand it that I’ll switch off from everything you say thereafter.

This is because we can only think about one thing at a time. With a mind like a filing cabinet, every detail is separated and stored in an individual folder. If we’re thinking in a certain way about a certain thing – say, file Z284 in Drawer C (the book we’re reading) – then how on earth can we suddenly start thinking about something else – file B827 in Drawer F (the gas bill), for example? So we focus on the first file, and the others cease to exist – at least until they come knocking on the door.

And when we try to do too many things at once, or switch from thinking about one thing to thinking about another, we often screw up our whole filing system. We open a drawer, take out a file, study the page; then we open another drawer, take out another file, look at it; open a third; and before we know it, all the drawers are open, we’ve got files all over the place, we can’t work out what goes where and can’t put anything away or let anything go, our thoughts spiral round and round and, unless we manage to stop this process, we go into what is affectionately called an ‘autistic meltdown’. That’s what it’s like having a filing cabinet for a brain (and that’s without mentioning how, because our thoughts are separated into different files, we focus on the details and miss the ‘bigger picture’ – we see trees instead of forests – but that is by the by).

Anyway, ‘what does all of this have to do with babies?’ I hear you ask. Simple. My house is a tip.

Actually, that’s putting it mildly. My house is, at current, a shithole. I know this because both of Lizzie’s parents have separately described it as a ‘disgrace’ and said that they would be embarrassed to have people over. Ouch!

To be fair, I don’t really notice the mess most of the time. We’ve been blaming it on having a baby – how can anyone have a baby and a tidy house? – but I’ve stumbled unannounced into two houses in the past fortnight who have kids the same age as Izzie, and their houses are freaking immaculate: toys put away, the sideboards clear of stained coffee mugs, no dishes in the sink, clothes hung up instead of strewn over the backs of chairs, everything in its place. Where in God’s name do they find the time or the energy to do that? What makes us so different?

The answer, which has been eluding me for so long, is horrifyingly obvious: they don’t have autism; we do.

To have a tidy house and a baby, you have to be able to multitask. You have to be able to keep one eye, or part of your brain, on the baby and the other on the washing, the ironing, the cleaning. And that’s not something I’m capable of doing.

When I look after the baby, I look after the baby. That’s my job, that’s my focus, and that’s what I do. When I tidy, I tidy. I can’t do both at the same time. So I leave the tidying to the evening, after Izzie’s gone to bed, by which time I’m exhausted and tend to flop down on the sofa or, to be entirely honest, obsess over random things like making lists of all the WWE wrestlers from my teens who are now dead, or researching the million-and-one rebuttals to 9/11 conspiracy theories, or writing 10,000 word treatises on why Jack the Ripper was not Arthur Sickert (take that, Patricia Cornwell!) – you know, useful, productive things like that.

Raising a baby as a person with autism is surprisingly mentally taxing. There is so much information to process, so many sensory inputs and new experiences to file away, my brain is constantly distracted. I used to go to bed between midnight and two every night, getting around six hours sleep – now, I’m lucky to be able to function past ten. That’s how draining it is.

I’m not entirely sure how to rectify this situation. I mean, the house is mostly clean – it gets hoovered, the sides are anti-bacced and we’re still sterilising the baby’s bottles; bleach down the toilets, dog poo picked up, nappy bin emptied regularly, rubbish put out – it’s just got stuff everywhere. And until I can figure out a way of thinking about two things at once without tying my thoughts into knots, that’s the way it’s going to remain.