Depression is not a lifestyle choice. It chooses you, you don't choose it. Amazingly, the majority of people still seem to think that depression is an indulgence that one chooses, the way one chooses to splurge out on that Marc Jacobs scarf with the pretty stripes or a second helping of tiramisu. "People!" as Carson is wont to say on Queer Eye for the Straight Guy. "Enough already!" When are people in this country going to wake up and realise that depression is a serious illness?

When are we going to stop treating people suffering from depression like whiny, red-eyed couch-potato defeatists who could snap out of it if they only turned the temperature up on their stiff upper lip? Depression is as painful and debilitating as any severe physical illness. And yet there seems to be a national mental block that makes it impossible for people to comprehend that, whether physical or mental, illness is illness. Just because you can't see it, it doesn't mean it's not there. To write depression off as an indulgence is to buy lazily into a skewed hierarchy of illness. The same people who are quick to snap, "Cheer up", "Pull yourself together", "Chin up, old boy" or, my personal favourite, "Life could be worse", are the exact same people who would bend over backwards to help if you turned up to the office on crutches nursing a broken leg.

Depression is embarrassing for the stiff-upper-lip brigade. Look at the way the royal family still use Princess Diana's "mental state" as a get-out clause for any awkward news story they need to get rid of. It's so easy! Cite her mental problems and it's all over. "Oh yes," say the masses, "we forgot, she was unstable!" It's incredible how depression and mental illness are used to invalidate a person. Look at the way the Sun dealt with Frank Bruno being sectioned. "Bonkers Bruno!" I'd love to see Sun editorial staff responsible for that headline thrown into a Freaky Friday scenario in which they trade places with Bruno on the day he was sectioned. It could be screened as a reality-TV show. Oh, the fun we'd have!

Aside from causing the stiff-upper-lip brigade to break out in a cold sweat, depression also frightens the living daylights out of middle England, a demographic that thrives on scare stories. In their paranoid minds, the leap from mildly depressed person to psychopathic axe murderer is but a copy of the Daily Mail away. And this is where there's much work to do. The taboos and stereotypes surrounding mental illnesses such as depression are stoked by a lack of information.

Why is it not common knowledge that there are many different types of depression? Probably because people don't want to talk about mental illness. It's depressing, they say. As someone who has been on and off antidepressants for 15 years, I find it infuriating to hear the word "depressed" misused so infectiously in everyday life. Depression is not groaning at the bombed-out state of your current account, moping for a few weeks after a break-up or hating your job.

Depression is an agonising illness that takes over your life, screws up your brain chemistry, makes you cry over the silliest little things, kills your sex drive, shatters all interest in the things you usually love doing, isolates you from friends, partners and family, makes you sleep all day and lie awake all night, either exaggerates or assassinates your appetite, takes you to a point where you think it's quite normal to hurt yourself and lastly, when the alarm bells are screeching, makes a compelling case that you'd be better off dead. That is depression. It can affect anyone. It does not discriminate. It doesn't care what class you're from, what your sexual preference is, what ethnic group you belong to, what job you do, how old you are.

So throw out the cliche that depression is a class indulgence, a luxury that only the middle and upper classes can afford. This trite generalisation, while it may go down well with the Julie Burchill fan club, is laughably inaccurate. The point is this: people going through depression need compassion and understanding. It's an illness that leaves sufferers feeling cut off and voiceless. Telling someone who is depressed to pull themselves together is like telling an amputee to put his leg back on. Depression is not something that you choose to suffer from. Having lost one of my closest friends to suicide, I can vouch for that.