As children, almost all of us had the opportunity to discuss a very serious question: if you could have one superpower, what would it be?

Many children wish to be inhumanly strong, to manipulate natural and cosmic forces, or to live forever – all logical responses for anyone looking to help others or just to get their own way. But in every group, there is always somebody championing the cause of invisibility, to go anywhere and do anything without being noticed. It’s no accident that in a world overflowing with magical artefacts, Harry Potter relies most frequently upon his invisibility cloak.

Of course, the power must be qualified. Children who consider it usually stipulate that they should be able to alternate between visible and invisible at will, rather than being permanently invisible. And granting invisibility to people other than ourselves is something that we prefer not to consider – indeed, much of the debate over privacy in the twenty-first century stems from our innate, animalistic fear of being spied upon by predators whom we cannot detect.

But there’s also a beautiful temptation underlying the notion of invisibility, for it offers us the chance to see things without impacting them. We already know how other people act in our presence, but we wonder what more they might be saying behind our backs. Conversely, an invisible person could impact things without being seen, suspected or reprimanded. Or judged.

Having an invisible illness also has a strange beauty.

Those of us who experience them are constantly grateful that our disability does not precede us, that we can choose whom to confide in, when and how. We can make strategic assessments whenever we meet somebody new and weigh up whether we might be better off opening up or remaining silent.

The appeal of staying silent is, unfortunately, all too obvious. The knowledge that somebody suffers from a disability inevitably changes the way that they are viewed. They might become a subject of derision or discrimination, but even if that could be set aside, the stigma would remain. Whenever we come across someone who appears restricted, we automatically apply stereotypes and generalisations that we cannot unlearn.

Even with the purest of intentions, we subconsciously overestimate their need to rely upon others, underestimate the importance of their other features, and lower our general expectations of them. Someone in a wheelchair cannot avoid the impact that it has upon every first meeting and most interactions thereafter. Their weaknesses will always be controversial, confronting or awkward, but a go-to topic of conversation nevertheless.

People with invisible diseases, however, inherit a magical cloak that they can don whenever they wish to doff those preconceptions. They can allow others a chance to get to know them before having to display any confronting abnormalities. They can avoid the controversy… sometimes.

The reason for that hesitation is that, in flagrant contravention of the standards and stipulations that every child has a right to demand, the on/off switches attached to our cloaks are faulty and unreliable. Even when an illness is invisible, the restrictions it creates are real, constant and often all too visible. Chronic pain can be unpredictable and sufferers will sometimes find themselves in sudden and immediate need of a seat, or a stretch, or a bed. And such an eventuality becomes increasingly more likely over time, as the pretence of being pain-free continues.

At some point, the façade will break, and just like the revelation of any other secret, the delay in sharing the truth will create a sense of betrayal: Why was I lied to for so long? Why did they presume that I would overreact? Do they think that I’m prejudiced, spiteful and untrustworthy?

When you’re personally involved, it’s easy to overlook how quickly and easily the narrative just shifted from trust to deception, from weakness to rejection. Nobody chooses to have an invisible illness, and being expected to disclose it creates a perfect setup in which even being honest reinforces the stigma against it. The other drawback to invisibility, you will recall, is the fear that it can create.

And this is where it all culminates, the stigma, the unpredictability, and the ‘deceit’: The longer that we present ourselves as normal and pain-free, the harder it becomes for others to take our illnesses seriously. When a disease makes no logical sense and leaves no obvious signs, its very existence is called into question.

Anyone who witnesses me being physically active for a full afternoon will have every reason to be sceptical when, a few days later, I am suddenly ‘too sick’ to repeat the activity. I can’t expect them to know that my pain varies unpredictably, or that last time I had scheduled my entire week around being able to push through that event, allocating hours for bedrest before and afterwards. When I attribute my apparent laziness to a disease they’ve never heard of before, it comes across as little more than a pathetic, insensitive excuse.

And that impression is easily confirmed. Anyone looking to perform follow-up research will discover plenty of Google results declaring that the so-called symptoms of this so-called disease are all just in my head. The irregular and unconventional nature of the illness they so briefly encountered has already primed them to believe the denialists and doubt the patients, the doctors and reality.

Having an illness that is invisible can be both a blessing and a curse, a gift and a burden disguised as a choice. Whether we disclose it or hide it we cannot help but envy those who are deemed ‘conventionally sick enough’ to be taken seriously. Our desire for normality conflicts with our need for understanding, turning us into hypocrites. But we can’t help it; it’s the cost of being able to subsist in two different worlds.

The invisibility dilemma never goes away. Everyone who faces it is entitled to their own approach and even their own inconsistencies. For there are no easy or universal solutions, just as there are no actual invisibility cloaks. But if children around the world can believe in that magic, perhaps they can also grow up to share Dumbledore’s acceptance of the incomprehensible:

“Of course it is happening inside your head, Harry, but why on earth should that mean that it is not real?”