I was a late adopter of technology. In the 1990s, I lived off-grid. If anyone wanted me, they had to call my pager. When it buzzed, I’d walk two miles across fields to ring them back from a dusty phone box on a country lane. Even after I rejoined the modern world I remained a Luddite. I was late to email and so late to laptops that I wrote all my degree coursework by hand. I was years late to Facebook and only bought my first smartphone last summer. Not, on the face of it, the most likely person to become addicted to Twitter.

My relationship with it began during a long period of loneliness about a decade ago, in my mid-30s. I was living in New York, away from my family and friends, weathering a miserable break-up. The time-zone difference meant an ongoing glitch in communicating with people back home. Skype, with its two-second time lag and perpetually frozen screens, made me feel further away than ever. I wanted to talk to people who were awake when I was.

The thing I liked about Twitter back then was that it connected you with other people according to shared interests, the more niche the better. Exchanging links to articles led to shared jokes to direct messages to tentative meet-ups to full-blown let’s-go-on-holiday-together friendships. I went on a trip to Maine with someone I knew through Twitter. Twitter was where I met the man I’d marry, as well as half the people at our wedding.

It undeniably brought a lot of warmth into my life, but by 2015 I started regarding social media with a more suspicious eye. I was writing The Lonely City, an investigation into loneliness in the modern age, and had begun to think about the relationship between the internet and isolation. It was great for connecting strangers, but how much did it really foster intimacy? Performing for likes was not at all the same thing as being accepted for who you are, the necessary foundation for the high-risk act of intimacy. And how good did it really feel to conduct friendships in public?

Facebook Twitter Pinterest ‘Knowledge matters, but so too does the slower and more private act of thinking’: Olivia Laing on life after Twitter. Photograph: Matt Writtle/Evening Standard/Eyevine

After finishing the book, I changed my relationship with social media. I deleted my Facebook account, but stayed on Twitter, even though it had become palpably more adversarial, less friendly. Trolls, pile-ons, policing, the endless accusation of virtue signalling – it was increasingly hard to feel safe enough to say anything at all. The reason I didn’t leave was that it had become the place I came to for political news, especially during the seismic changes of 2016.

That year I slept with my laptop on the pillow beside me, waking multiple times in the night to check my feed. Twitter was my constant companion, the lens through which I watched the EU referendum, Brexit, the American presidential campaign and Trump’s election. I couldn’t look away. Even though I suspected that the speed and strangeness of events had something to do with social media, I still believed social media was the place to find out what was really going on, hours before the ponderous newspapers caught up.

I wasn’t so much addicted to the spectacle as to the ongoing certainty that the next click, the next link, would bring clarity. I felt like if I watched everything, if I read every last conspiracy theory and threaded tweet, the reward would be illumination. I would finally be able to understand not just what was happening but what it meant and what consequences it would have. But there was never a definitive conclusion. I’d taken up residence in a hothouse for paranoia, a factory manufacturing speculation and mistrust.

The more I consumed, the more I was drained of all hope

I recently read a description of the effects of the intensely addictive opioid OxyContin as total contentment and satiation. “I feel as if I have suddenly gained all that I want in life and no longer have anything to fear,” a user said. “I am perfectly content both mentally and emotionally.” You can at least understand the appeal of that. But the drug I’d got hooked on was terror. I stayed up all night reading Nazi websites and Reddit threads by “incels” that proposed the answer to so-called sexual inequality, by which they meant a woman’s right not to have sex with someone, was redistribution, by which they meant the loss of a woman’s right not to have sex with someone, which the last time I looked was called rape.

The more disturbed I became, the more urgent the need for understanding. On 2 August 2017, I decided to start writing down everything I encountered online, from the trivial to the momentous, in a document that over the next seven weeks became a novel, Crudo, written in real time. I was conducting an experiment. I wanted to record both the news itself and the effect of consuming it in a historically unprecedented way, to capture what it was like to live alongside – inside – such a fast-moving cycle, to be saturated by malign information.

The thing that made Twitter at once exciting and terrifying was that it constantly overwrote itself, a deluge of information, new things stacking up by the second, so that the events of even a week ago seemed ancient, barely recallable history. It went by too swiftly to process and so I stood at the edge of the stream and fished things out, to think about more slowly.

The first item I recorded was Trump’s sacking of Anthony Scaramucci, who had so briefly been the White House director of communications that a joke went round that fruit flies had longer life spans: 56,152 likes. Over the course of the summer, I interrupted my own wedding to record the resignation of Steve Bannon. Twitter was the source of news, it was where I found out about the Grenfell fire and militias marching in Charlottesville, but it was also increasingly the news itself. Trump used it to threaten nuclear war, taking breaks to trashtalk the FailingNewYorkTimes. Hunched over my laptop, I wrote it all down.

One of the reasons I’d told myself I needed to be online, especially as the world lurched to the far right, was that it was our duty as citizens to be educated, alert, awake. But recording the process over months showed me that the actual consequence was that I was hypnotised by horror. The more internet-reality I consumed, the more I sat there, numb, paranoid, drained of hope.

I decided to leave not because I didn’t want to know how bad things were. I didn’t want to cut out the news entirely, like those smug people who move to the woods or give up dealing with money and don’t realise the reason it works for them is because they’re white and 22. I left because I felt like my ability to act or think or even feel was being damaged irreparably. All I could do was react. I didn’t want to be so polarised, or to lose all faith in the ability of humans to learn, to discuss, to change their minds. I didn’t want to lie in a bath of poison run by Nigel Farage and Donald Trump.

I deactivated my account in the autumn of 2018, telling myself that I was just going to take a short break. As long as you log in within 30 days, you can keep your account, even if you deactivate it again immediately. At first I wrote the 30 day dates in my diary, but at some point I forgot and when I logged back in the network didn’t know who I was.

It was such a relief to be offline. If I met people, I didn’t already know that they had once expressed an opinion I despised. Instead I could talk to them. Maybe I’d change their mind. Maybe they’d change mine. I was sick of dogma. What I wanted was nuance and openness. Honestly, I think that’s where change comes in the world, and not by shaming and exiling people on account of statements they’ve typed into a website.

A 2014 study by Dutch neurologists suggests that when people see an accident, they can’t at first empathise, let alone reflect, make decisions or act, because they are bombarded by an instantaneous flight/freeze/fight response, which has to wear off before they can think in more helpful ways. It seems to me now that being on Twitter was like watching a perpetual car crash.

Everything happened on a knife-edge of emotional reactions

Over the years that I was there I saw footage of hundreds of people killed and injured: African-American men choked to death by white police, stonings, murders, a man in a cage set on fire. I wanted to know what was happening in the world, but there was never enough time to process the information, to consider responses or causes, even to mourn. Everything happened on a knife-edge of emotional reactions, which in turn fuelled more confusion and distress.

I didn’t leave social media altogether. I stayed on Instagram, where there is very little politics and very little disagreement. Looking at photographs of gardens and food makes a nice antidote to the book I’m working on now, which is about violence and freedom. Although the material is just as heavy as the things I saw on Twitter, I’m encountering it primarily by way of books, which contextualise and analyse the raw data of distress.

Because of Brexit, this spring I’ve found myself edging back towards my old habits of news consumption. For the past few weeks, after everyone has gone to bed, I gorge on newspaper websites. But no matter how much information I acquire, the story has moved somewhere completely unexpected by the next day. The information isn’t helping, not in its speed and not in its abundance. Knowledge matters, but so too does the slower and more private act of thinking.

It seems to me that the most dangerous state to be in right now is numbness, and that our numbness facilitates precisely the cruelties it’s caused by, a vicious circle it’s hard to know how to stop. Over the last two years, I’ve become obsessed by something the painter Philip Guston said in 1968. He’d been thinking about the Holocaust, especially about the concentration camp Treblinka. The mass killing worked, he explained, because the Nazis deliberately induced numbness in both the victims and the tormentors. And yet, a small group of prisoners did manage to escape. “Imagine what a process it was to unnumb yourself, to see it totally and to bear witness,” he said. “That’s the only reason to be an artist: to escape, to bear witness to this.”

I think about those words every time I wonder about returning to Twitter, climbing back into that numbing bath of catastrophic information. He didn’t mean escape as in run away from reality. He meant unspring the trap. He meant cut through the wire.

Crudo by Olivia Laing is published by Picador in paperback at £8.99. To order a copy, go to guardianbookshop.com