The names in this article have been changed for privacy reasons.

I used to shoot intense glares of disapproval at those I saw parking in disabled spots and taking up the special needs seats on public transport, who seemed perfectly capable.

But my friendship with a woman who was born with cystic fibrosis has changed all that.

Invisible disabilities include mental health issues, multiple sclerosis, endometriosis, chronic fatigue syndrome and diabetes to name just a few. With one in five Australians suffering from a disability, the amount of those who live under the cloak of an invisible illness is higher than some may think.

Sarah’s illness zaps her of her energy, clogs her lungs with mucus and nearly halves her life expectancy. But she looks like any other 21-year-old and has spent her life battling between the need to be understood and the need to not be simply seen as the “sick kid”.

Image: iStock.

A frank, dark humour we share keeps her illness from becoming a taboo subject. We’ll often casually joke that she has the lungs of an elderly woman and she’ll brag about how much phlegm she’s coughed up that day. That’s just part of how we both deal with her illness but it becomes much more difficult with people who don’t know her well.

“I find it really hard how sometimes I want a different response from people, but then how are they supposed to know what to say unless they’ve been through it? And I don’t want to be the person who always goes on about their illness,” Sarah says.

The problem is that people can’t tell that she’s sick, so when they eventually find out, they’re shocked and don’t know how to treat her anymore. (Watch: Disability advocate Stella Young discusses what it's like to live with a disability. post continues after video.)

One common response is admiration mixed with a hint of pity. The “wow you’re so brave to be living with that!” kind of line, which makes Sarah uncomfortable time and time again.

“When people say 'you’re so brave' I say, 'no, I have two choices. I’ve wallowed in self pity for a long time and I will in my future years, but you’ve just got to get up and get on with it, cause otherwise you’ll be miserable for the rest of your life'.”

When she applied for her first job, Sarah didn’t tell her employers about her CF. “It was more a conscious decision not to feel obliged to tell them, rather than keeping it a secret,” she says.  Her illness is kept on a need-to-know basis, in order to live the most normal life she can.

Image: iStock.

She refuses to sit on the disabled persons seats.

“It’s more out of my own decision to prove that I don’t need them, and my own need to prove that to myself. I’ve never thought I have a disability, I’ve never looked at those signs and thought they’re for me. I joke they are but I don’t actually believe that.”

In her eyes, she’s one of the lucky ones. Some people aren’t able to decide who knows about their illness, and don’t have the power to decide to not use the disabled seats. But being able to “pass” as a non-disabled person can also lead to your needs being ignored.

This inner pressure to live life as if she didn’t have CF means Sarah sometimes struggles with asking people for their understanding. She hides so much of her illness that people easily forget she even has it, which can result in a barrier between her and everyone else; much like those who suffer from mental illness.

“As much as you can sympathise with someone, it’s hard to know unless you’ve been through it,” she says.

While Sarah deals with Cystic Fibrosis every day, the absence of a constant physical reminder means some people become ignorant to her reality. Situations where people complain to her about their sore throat or a cold they can’t seem to shake off can become frustrating. (Post continues after gallery)

“I don’t want people to think I’m having a go at them, but it’s instances like that where people really don’t get what I’m going through,” she says. “That’s your situation and that’s really crap because your normal is better than that, and coming down from that is really rough. But that’s my normal, and trying to get the balance of wanting people to understand but also let them go through their own stuff is hard.”

Her resilience, selflessness and spirit has inspired me my whole life, and has taught me that you never know what’s going on in someone’s mind or body.

So as I stand on the bus, noticing a seemingly very healthy-looking woman take up a spot reserved for pregnant women and the elderly, I hold my tongue. That could be Sarah. That could be any one of the many Australians who are living with an invisible illness, and they need my understanding.

More information on invisible disabilities is available here.

Image: iStock.