I once had a friend who was almost suffocated by cheesecake. She was a nice woman – let's call her Penny. I met her in a hospital, as you do. Penny was undergoing treatment for breast cancer, and let's just say she was a little bit pissed off with it. Not the breast cancer, but the way she had become "Poor Penny with Breast Cancer How Tragic She's Only 38, You Know". Penny felt that everything interesting about her had been stolen. She was no longer a clever woman who knew a lot about how ants form orderly societies by leaving chemical trails for each other, or how to get the best deal on a new washing machine. Cancer became a definition of who Penny was.

It had become quite literally the first thing people would ask her about. Not her opinion of Desperate Housewives, not the life cycle of caterpillars or any number of other interesting things she knew about. Just cancer. How her treatment was going, whether she looked "well on it" or "not so great" … and because they could offer her nothing else constructive, they gave her food to show they cared. It started with a few casseroles for the slow cooker when she had chemo days, and escalated to cheesecakes and homemade choux pastry at an alarming rate. Weight loss was never an issue for Penny through her chemotherapy – she had raspberry pavlova to raise her spirits. I bet she still has cheesecake in her freezer from that time. And not just that, people she barely knew suddenly laid claim to her. A bloke with halitosis she got off with at the office Christmas party in 2004 ran a marathon with her face on his T-shirt.
I had reason to remember Penny and her profiterole problem over Christmas, when I myself was ill. At the beginning of December I went to my GP, he agreed with me that something was horribly wrong and I was prescribed both chemical and non-chemical treatments. I was honest, I told friends and family that I was battling against something nasty. I confess that I was partly hoping for a shower of cake, but unlike Penny's friends mine aren't terribly good cooks. But there was something else, too. Although aware of it, very few people asked me how my treatment was going. Even fewer told me if I looked better, or still much like I was auditioning for a new version of Worzel Gummidge. People went quiet, distant. They left me alone even when I opined about how isolated I felt. I had very few people I could talk to about my condition, and only fellow sufferers seemed to care. Why?
I didn't have breast cancer. I was depressed.
There's no easy way to slide depression into a conversation. When people ask after you when you bump into them in the supermarket, it's OK to say you have a nasty cold or some irritating health issue (especially if they've caught you in the haemorrhoid cream aisle), but not OK to mention that it's the first time you've left the house since December and you're feeling pretty pleased with yourself for venturing out to buy toilet paper. Depression is invisible. You can't see it (though you might be able to smell it: at my worst I would go without showers for days at a time), it has no obvious physical symptoms, and people don't like to talk about it.
Why not? Let's examine this in more detail. If you ask about my depression, am I likely to: a) Shout "You know? At last, I'm free!!" And run around ripping my clothes off in the detergent section of Morrisons. b) Corner you with a monologue about how my therapist made me realise – remember that goth boy who looked a bit like Nick Cave who dumped me when I was 15? – chances are we wouldn't still be together if dyeing my hair black had changed his mind, after all.
c) Scream "YOU DON'T UNDERSTAND ME!!" And make a break for the nearest slammable door, bedroom or otherwise. Yes, people are often scared they'll say the wrong thing and show their ignorance of depression. Even though it's an issue for many, most of us know very little about it.

But if you ask a polite, delicate question it's much better than the people who think they know everything about it, who will tell you that they were depressed for THREE WHOLE DAYS when their goldfish Colin died, but then they remembered there's more to life and bucked their ideas up. Can't I just … stiffen my upper lip? Get a grip? Get some perspective? Get out of the house and go for a nice walk? I'm sure to feel better with some fresh air. It's like telling someone with a broken leg that going for a nice jog around the park is sure to improve matters. Just stop. Admitting you know nothing is better than pretending you know everything.

But there's another thing, the most depressing thing about depression. Just over a month ago I wrote this on my own blog. It brought by far my most views and my biggest response. People telling me they had suffered the same sense of isolation, the same insecurities and loneliness. It was overwhelming. But you won't see it in the comments. Almost every single person told me in private. Because they were scared of what others may think, scared their employers would see, scared it may harm their future prospects.

I'd love to live in a world where people can talk about this and not worry about the consequences, where mentioning you've been depressed doesn't result in an awkward silence. I'd love a world where people send me choux pastry when they know I'm going through a bad patch. I'd love the kind of support that Penny had, even though it irritated her.

I’m recovering well, but if anyone wants to send me cheesecake they can message me on Twitter and I'll happily pass on my address.

Tania Browne posts on Twitter as @Cherrymakes. Time to Change campaigns to end the stigma and fear around all kinds of mental health problems. You can find them at time-to-change.org.uk