"I still remember the day my brain broke"

I was in a supermarket car park in Wales, in my early teens, on holiday at my grandparents. It was a time of trips to the beach, limitless Welsh cakes, and peanut butter and jam sandwiches. But all was not well. Inside my head, a storm was brewing.

I’d had obsessive thoughts for as long as I could remember. As a child, I’d lie awake at night, worrying that the house was going to burn down, or that something terrible would happen to my family if I didn’t go through my ritual of prayers. Once, I remember sitting in church, becoming gradually convinced that the man behind me was going to kill me.

But on this particular day, for no apparent reason, something shifted. A switch had been flicked inside my brain. There was white noise. I had become acutely aware of my own thought processes, and my head hurt. Like a million tiny birds pecking at the inside of my skull, my mind began to buzz with repetitive thoughts – thoughts that I’d do anything not to have. My brain had got stuck.

I didn’t realise it then, but this was the beginning of obsessive-compulsive disorder (OCD). Far away from the media stereotypes of neatly organised CD collections and immaculate sock drawers, I wouldn’t get a diagnosis until my 30s. In those intervening years, unable to explain what was going on in my own head, my mental health sank to depths that I didn’t know existed. But it turns out that I wasn’t alone. There’s a whole world of people out there who are tortured by their thoughts, afraid to get help and unable to tell even their own families. This is what it’s really like to live with OCD.

Just a thought?

The average person has tens of thousands of thoughts every day. Most of these are fairly mundane and ordinary, but given the sheer amount of chatter running through our brains, it’s no surprise that we sometimes get strange, even disconcerting, thoughts that appear to come from nowhere. You’re walking across a bridge and suddenly think of jumping off. You’re cradling a newborn baby and get an image of throwing her down the stairs. You enter a hushed cathedral and have the sudden urge to swear at the top of your voice.

Psychologists call these ‘intrusive thoughts’, and research has shown that everybody gets them. “When we asked people whether they experience these kinds of thoughts, 93 per cent said yes,” says Prof Paul Salkovskis, Professor of Clinical Psychology and Applied Science at the University of Bath. “In a follow-up study, we tried to interview those who said they didn’t, and they didn’t want to speak to us. I’m as convinced as it’s possible to be that the real figure is 100 per cent.”

Salkovskis believes that we’re hardwired to have these thoughts. “Intrusive thoughts are our brain’s way of dealing with uncertain circumstances, which we’ve had throughout our evolution,” he says. “Thoughts will come into our minds that are loosely connected with what’s going on around us – some of them will be good ideas, and some will be bad.” According to this view, intrusive thoughts are part of our brain’s in-built problem-solving system – a literal brainstorming mechanism that’s designed to keep us alive. Just as our ancient ancestor, when faced with a tiger, might have thoughts about running away (good idea) or trying to befriend it (bad idea), so our brains today are constantly coming up with ideas to help us make sense of our surroundings – ideas which might be helpful, weird, or just downright scary.

Most people are able to dismiss the unhelpful intrusive thoughts as quickly as they arrive. But someone with OCD is unable to ignore them. They’ll interpret them as saying something fundamental about who they are. What if I’m a danger to myself? What if I harm this baby? What if I’m evil?

It didn’t take long for my OCD to snowball. In that car park, my brain began to fire obsessive thoughts at me about my sexuality. I started to constantly obsess over whether I was gay, to the extent that I was checking my attraction to every single person I saw. At this stage, I thought it was just me grappling with my sexuality, but by the time I was 20, things had got a lot darker.

My intrusive thoughts began to convince me that I was a horrible, evil person. I’d walk down the street, scared to meet people’s eyes in case I had a terrible urge. If I was using a knife, I’d worry I’d suddenly lose control and stab someone. If I saw a serial killer in the news, I’d worry that I was going to turn into one. If I saw a kid in the street, I’d get intrusive thoughts that I was going to turn into a paedophile.

It was mental torture. OCD is known as the ‘doubting disease’ because it makes you question everything. It slowly erodes your sense of identity, and every waking hour becomes consumed with unwanted thoughts. I developed acute anxiety, depression, and debilitating headaches. Even going to the shops became an ordeal, as just one intrusive thought could bring my anxiety to tipping point. It was like living two lives at once, and there were days when I wanted to go to sleep and not wake up again.

Anatomy of an illness

For over 15 years, I was in the grip of OCD. But there are a lot of us out there. It’s an illness that affects an estimated 12 in every 1,000 people – that’s almost 800,000 people in the UK alone – but it is often misunderstood as being a trivial personality quirk, or a penchant for order and cleanliness (see ‘5 myths about OCD’, below).

OCD can come in a number of guises, but it always follows the same pattern. First is the unwanted thought (this can also be an image or an urge). This is the ‘obsessive’ part of the disorder. OCD can attach itself to pretty much any theme, but common ones include thoughts about harm (either to yourself or others), suicide, contamination, disease, blasphemy, forbidden sexual thoughts, and relationship and sexuality obsessions.

The intrusive thought causes anxiety, so the sufferer feels compelled to do something to relieve it. This is the ‘compulsive’ part of the disorder, and it could involve washing, checking, counting, repeating a phrase, praying, going over things in your mind (‘rumination’) or a whole host of other coping mechanisms. These behaviours can be physical or (as in my case) purely internal, invisible to everyone except the sufferer. This internalised form of OCD is often called ‘Pure-O’ (purely obsessional OCD), but this is something of a misnomer, as compulsions are still very much involved – they’re just going on beneath the surface.

Once a compulsion is carried out, it will only have a temporary effect. Soon enough, another thought or trigger will occur, and the compulsions will ramp up again as the sufferer attempts to calm the ever-growing anxiety. It’s a vicious loop, and one which can easily mushroom out of control. It’s no surprise that OCD sufferers are 10 times more likely to take their own life.

I developed a number of ways to cope with my anxiety. All day, every day, I’d monitor my thoughts. If I had one that I deemed ‘bad’, I’d immediately have to think of a ‘good’ one to counteract it, or I’d wrestle with the thought until I was sure it didn’t mean anything. I’d monitor my facial expressions in case I somehow developed an ‘evil’ face, and I wouldn’t be satisfied until everything in my head felt ‘just right’.

But by trying to control my thoughts, I only made them worse. If someone tells you not to think of a pink elephant, you’ll immediately have pink elephants stampeding through your head.

OCD is a shape-shifting beast. As I found out, the themes can evolve over time, and they often latch on to whatever the sufferer holds most dear. The new mother has an image of harming her baby. The priest thinks of blasphemy. Zoom out, though, and interesting patterns begin to emerge.

“When I started working with patients in 1977, no one had intrusive thoughts about contracting HIV/AIDS,” says Salkovskis, “but then in the 1980s that became a common theme. OCD is often centred around whatever is society’s ‘invisible threat’. Today, intrusive thoughts about being a paedophile are common. A few hundred years ago, most of the thoughts would probably have revolved around religion.”

Salkovskis is keen to stress that people with OCD pose no danger. “There is absolutely no record of anyone with OCD acting on their obsessional thoughts,” he says. “The thoughts are completely at odds with the person’s values.” He offers an example of a therapy exercise he used to carry out with people who experienced intrusive thoughts about harming others. “I used to keep a sharp kitchen knife in my drawer, and I’d ask the person to hold it to my neck. I’m still here!”

Always hope

I was formally diagnosed with OCD last year, and I’ve recently finished a course of cognitive behavioural therapy (CBT). This talking therapy is the go-to treatment for OCD (sometimes in conjunction with anti-anxiety medication), and it involves helping sufferers to see their intrusive thoughts for what they are – meaningless brain piffle. In my case, it involved a technique called ‘exposure and response prevention’ (ERP), in which I had to write out scripts of my most feared thoughts and learn to tolerate the anxiety without performing any compulsions. ERP can also involve physical exposures, as with the knife example above. The idea is to accept and embrace the thoughts, until you’re so used to them that they no longer cause anxiety.

I sometimes wonder whether I was destined to develop OCD. Did something go wrong in my brain’s wiring as I was growing up? There’s certainly evidence that the OCD brain is firing differently. A body of research points to the relationship between three brain areas: the prefrontal cortex, striatum and thalamus. In people with OCD it seems that a neural loop between these regions becomes hyperactive, which neuroscientists think is linked to the repetitive thoughts and behaviours.

But it’s difficult to know whether these brain differences are the cause or the consequence of the OCD. And it’s likely that a number of other factors play a role. OCD is often linked to ‘thinking errors’ in the way someone sees the world. These cognitive distortions can begin to form in childhood, and they might include an inflated sense of responsibility (“I must not upset or disappoint anyone in any way.”), a desire for 100 per cent certainty (“how can I be certain that my partner loves me?”), or the belief that having a nasty thought is as ‘bad’ as acting on it (“I’d be locked up if people knew what I was thinking.”).

OCD can also be triggered by a traumatic event, and there’s likely to be a genetic component, too. A 2011 meta-analysis looked at 14 separate studies involving identical and non-identical twins, designed to tease apart the relative contribution of genetic and environmental factors in someone developing OCD. Genetics was found to account for around 40 per cent of the variance in OCD behaviour, with the remaining variation down to environmental factors.

However my OCD started, I still have it. But I’m beginning to see the light through the fog. Like everyone, I still get intrusive thoughts, but I’m getting better at letting them go. It took me years to find help, and that’s not uncommon. In fact, there’s so much stigma and misunderstanding around OCD that the average person goes 12 years between the onset of their illness and being diagnosed. That has to change.

There are sure to be a lot of people suffering in silence, especially with the purely internalised form of the disorder. “People with this type of OCD can get away with it not being noticed,” says Salkovskis. “Tormented though they might be, they can go for longer before they hit the crisis point.” For anyone who thinks they might have OCD, but is worried about voicing their thoughts, the OCD-UK charity has created a GP icebreaker for taking along to the first doctor’s appointment. “I’m now at the stage,” it reads, “at which I need to appeal to you, as a professional, to help me.” There’s a particular tragedy in somebody suffering for something which, ultimately, is not their fault.

For Christmas, I’d like a time machine. My first stop will be that supermarket car park in Wales, and I’ll give that kid just one piece of advice: there’s no such thing as a bad thought. And then I’ll let him know that he’ll be OK. It won’t be easy, but he’ll be OK.

For more information and support, visit ocduk.org.To read the thoughts and experiences of people with OCD, visit thesecretillness.com.

Five myths about OCD

Repetitive handwashing is one of the most well-known forms of OCD compulsion, but it only affects around a quarter of sufferers. Similarly, compulsive checking (e.g. taps, locks, light switches) affects around 30 per cent of sufferers.

Often confused with a liking for order and neatness, OCD is an anxiety disorder, characterised by frequent, distressing, and unwanted thoughts. A need for order or symmetry can sometimes arise, but this will be driven by an unbearable, underlying anxiety.

Not all OCD compulsions are visible. Around a quarter of OCD sufferers carry out purely covert, internalised compulsions. These might include ruminating, praying, suppressing or neutralising thoughts, mental counting, and avoiding certain situations and places.

There’s no joy in OCD. The World Health Organisation once ranked it as one of the ten most debilitating illnesses of any kind, in terms of lost earnings and diminished quality of life. At least one-third of people with OCD also suffer from depression.

The average age of onset is 20, but OCD can also affect adolescents, as well as children as young as four. Making a diagnosis at this age is especially tricky, as repetitive behaviours can also be a completely normal part of child development.

• This article first appeared in issue 313 ofBBC Focusmagazine - for the latest science news, discoveries and innovationssubscribe here.