Your extremely compelling book, Because We Are Bad, details your life with obsessive compulsive disorder. You are 23 now and your book gives the impression it has always been with you. But was there any starting point as such, and if so, what was it?

I don’t remember ever not living with OCD. From as early as I can remember, there were two of me in my head, and my brain was filled with weird, uncomfortable thoughts. I heard my OCD as a voice – “she” or “my friend”. There was never an “I” in my head. It was always, “We should do this,” or, “We think that … ” It’s unusual to experience OCD like this, but not completely unheard of.

OCD differs from person to person – how did yours manifest?

For the purposes of making this easier to understand, I normally talk about things “I” did when I was younger, as talking out loud as “we” can be disorientating.

My earliest memories of OCD centre around having an innate feeling that something bad was going to happen and that I was a bad person. In reception my teacher sent us all home with a letter, and we (“my friend” and me, henceforth throughout these questions called “I”) “just knew” that it was going to say something bad about us and that it needed to be hidden from my parents so as not to be in trouble. Other early memories include thinking my sister might die in her sleep, and repetitively crawling up and down the stairs to check on her, before praying for hours. As I got a bit older I started to have frequent obsessions that I might have done something bad and that I needed to compulsively make lists of what those things might be. I had bizarre thoughts that I could cause someone to haemorrhage just by brushing against them, or kill someone just by thinking it. Some of this may not sound like OCD to your average reader, but it’s important to remember that to have OCD merely requires that you have obsessions (unwanted thoughts and images) and compulsions (the action, whether physical or mental, that you take in response), and that they cause you significant distress.

Tell us about the moment your interior world (what was going on in your brain) collided with your exterior world.

By age 16, my list making had gotten out of hand. To give you an example of how this might work – say I’m walking down the road with a girlfriend and I feel that she has come into my personal space, I would start to worry that I smelt bad, and that she could smell it. So then I take the letter S for space and put it on a list. Then maybe a passerby walks past and bumps into my arm, and I take the letter A for arm because I feel that I might have caused them an internal injury. Then a child goes by, and I’m thinking, “Dear God, please do not let me look at that child’s bum because if I do that it might be caught on camera and someone might think I’m a paedophile,” so then I take the letter B for bum. Then my girlfriend starts talking about a mutual friend, and I’m worried I pull a funny face and it looks like I don’t like that person, so I take the letter F for face. Then I’m repeating, SABF, SABF, SABF. That could be my list from 30 seconds to a minute, so you can imagine how many letters I could have in a day – it could be hundreds. When I was 16, I think I just got to the point where I couldn’t go on like this. I got myself sent home from boarding school, and basically decided to stop getting out of bed.

What’s the most useful help you have received in dealing with your disorder?

When I came back to school I saw the school GP and was able to tell her a little bit about what was going on. She referred me to a psychiatrist for cognitive behavioural therapy. CBT is a talking therapy but it’s not really like traditional psychotherapy in that it is less centred on thinking about what happened, and why, and rifling around in the unconscious, and more about focusing on changing the current behaviour in the moment. It’s essentially about retraining the brain, and it is the first-line recommended treatment for OCD.

In OCD, it involves exposure therapy, where you feel the obsession come in, and rather than doing a compulsion like you normally would, you basically “sit with” that obsession. So for me, that might mean that rather than taking the letter S for space and wondering whether someone thinks I smell, I have to say, “OK, well maybe they do, so what?” Then I might have to take it a step further and not shower for a day, just to see how that feels. Over time I found that by doing this my thoughts became less scary – they lost their power. More recently, I’ve been having more traditional psychotherapy, which does involve looking back at my past more, and I’m finding it to be very helpful.

What is the most misunderstood thing about OCD?

The biggest misconception about OCD is that it’s about being a perfectionist or liking things “just so”. In reality, OCD isn’t really about anything. It just involves having obsessions and compulsions, and only some people with OCD have the straightening and tidying compulsions that we traditionally associate with OCD. Also people seem to think that OCD is a cute “quirk” – many take pride in being “soooo super OCD about their pencil case”. But OCD is not enjoyable – if you “totally love being OCD” then you do not have OCD. One of the criteria for having OCD is that you spend more than an hour a day doing it. The World Health Organisation has ranked OCD in the top 10 most disabling illnesses of any kind globally.

What has OCD taught you about human nature?

That brains are right complex. And that you never know what someone’s going through behind the smile.

Your book is deeply personal. Is it difficult having people know so much about you and the secret thoughts that made you think you were a terrible person?

Yes! I started dating this guy and he was all, “So shall I read the book or not?” And I was like, “Dear God, please DO NOT read the book!” Not that I wouldn’t have wanted to tell him about what I go through in time, but if someone I care about is going to find out that I worry about people thinking I’m a sexual predator, I’d kind of rather they heard it from me.

What did you want to achieve by writing it?

Well it’s unlikely you’re going to write something so exposing without very good reason. I had just gotten to a point where I was really tired of people having such a limited understanding of what it really means to have OCD. OCD is the fourth most common mental health condition, yet most people have no idea about how it actually works. I get really annoyed that I had no idea about any of this stuff when I was younger, and therefore I never told anyone. I didn’t know because my only understanding of OCD was that it involved being a perfectionist. So when people use the phrase in the wrong way, it literally costs people years of their life, because it stops them having any real understanding of what they’re going through and getting help.

You talk about “getting better”. Is it something you can completely recover from?

People are really, really, divided on this. It tends to be that the people who have gotten better say, “Yes you can!,” and the ones who haven’t will say, “No, you never really do.” Personally I believe that you can, because I have seen other people do it. So if I’ve seen something happen, then I’m going to believe it, right? I can’t see a plane flying in the sky and then deny that aviation is a thing. But I also acknowledge that it doesn’t happen for everyone, and that we don’t really know why that is.

What’s the best bit advice you can give to someone living with OCD?

Feel the fear, and do it anyway!