'Go to Threshers would you, darling, and get three for a tenner?' It’s December 2001 and I am 18. As is often the case, we need more wine. But I’m not a naughty teenager drinking with my friends: I’m drinking at home with my mother.

More than this, she is an alcoholic – as am I. We just don’t know it yet. So I won’t get in trouble for drinking or smoking cigarettes at home or be sent to my room in disgrace. My behaviour is completely normal. In fact, it’s encouraged. Some mothers and daughters go to spas together or go shopping. We drink and drink and drink. It’s fun, we tell ourselves.

And for a time, at the beginning, when the wine is poured and the kitchen blind is pulled down against the dark December night, it is fun. We laugh together in a cosy room, where candles are lit and somewhere a dog sleeps under a chair.

My mother Julia, a novelist, is witty and beautiful and engaging; she tells hilarious stories about people and says wise, unexpected things. I feel perfectly singled out in her company, as if I have been picked for some special privilege.

The love I feel for her in these moments is overwhelming.

Yet some hours later, when the sauvignon blanc bottles stand empty and discarded on the kitchen counter and the ashtray is full, we will argue, our voices slurred and faces swollen from drink. I can’t remember what the argument is about. It doesn’t matter because they’re all the same.

Have you ever looked at one of your parents and recognised something familiar in yourself?

A tone of voice maybe, when you catch yourself telling your children off, a tone so curt coming from your own mouth that it whisks you back to your childhood self with a sharp jolt. Blink and you’ll miss it, that weird voice coming out of your mouth 30 years after you first heard it.

Or perhaps you’ve seen your mother’s legs on a hot summer’s day and noticed, say, how you both have the same blue vein, in the same exact shape by the right knee. So similar it seems uncanny. But she’s your mother, why should this be so strange? Physical likeness is an easy way for us to understand inheritance; ‘I inherited my mother’s arms,’ people say with either resignation or pride. It’s simple.

But what if you inherit something like alcoholism? Is that even possible? I think it is – because I believe I inherited my alcoholism from my mother. Saying this, even now, feels shameful; too easy, like I’m passing the buck. And while I believe fault doesn’t come into it, I still feel bad for my mother for making such a claim, as if I have cast a slur on her genes.

When it comes to heredity and alcoholism, science can’t give us the definitive answer that would prove my theory. I wish it could.

Although experts now agree that alcoholism is up to four times more likely in the children of parents with an Alcohol Use Disorder (AUD), genetics isn’t the only factor that comes into play. Social and environmental factors such as trauma, poverty and poor mental health are also to blame. Nonetheless, the strongest predictor of alcoholism is a family history of it.

Accepting this as a society is hard because if something is inherited, how can it be cured? It’s easier to see alcoholism as the unfortunate by-product of social and cultural factors. Heredity, in contrast, makes everything feel so helpless.

This is certainly how I felt.

My childhood was spent watching my mother drink to excess. Beautiful, troubled, vivacious, she was rarely without a drink in her hand. Life with her veered between laughter at her chatter and afternoons spent waiting for her to wake up, and watching her stagger up the stairs before collapsing on the landing.

She first gave me wine aged five; a photo of me shows me wearing her sunglasses, jokingly holding a wine glass to my lips. Aping my idol. All harmless stuff, right? Until it’s not.

My mother believes that she, too, was ‘an alcoholic time bomb’ waiting to go off, having witnessed extreme alcohol use around her all her life. That bomb was detonated after her parents’ divorced when she was 13 years old, sending her into a spiral of terror and shock at her boarding school.

A troubled adolescence followed, where she learnt – as I was to – that alcohol could soothe unmanageable feelings. Drink soon became her medicine. At her boarding school, Benenden, alma mater of Princess Anne, Mum kept Dubonnet in a Ribena bottle in her washing cubicle, swigging on it every night.

The first time I felt the comfort of drink’s embrace was when I was 14, living at home in West London, attending the private girl’s day school, Francis Holland, in Regent’s Park. I was waitressing for a neighbour’s dinner party with a friend of mine. While the adults chatted next door, we decided to drink the wine in the kitchen. I didn’t do anything too terrible – but I don’t know how I got home.

That night of oblivion was the start of my love affair with alcohol. Just a year on, I was regularly arriving hungover at school. It was a prop for my emotions. I drank Mum’s wine and gin, topping up the bottles with water, or switching them around.

One night, when I was 15, Mum came home and found me drinking wine at the kitchen table. I thought she would be angry, but she poured herself a glass and sat down with me. The pact of secrecy between us had ended but another, darker pact of complicity had begun. Addicts like other addicts, after all.

The only time I felt really close to Mum was when we were getting drunk together.

It made me feel like the lights had gone on after a power cut.

My teachers were concerned that I seemed exhausted, falling asleep in morning lessons. Mum, meanwhile, had company as she tried to drink away her demons.

Somehow, amazingly, I got the grades to make it to university. But while most of my peers were discovering alcohol for the first time, my drinking moved into a darker dimension. I partied as hard as everyone else, but my nights often ended in my room, alone, with a razor blade and a bottle.

As well as drinking dedicatedly, I threw myself into my studies, graduating with a First, which I saw as licence to keep going the way I had been. Drinking was part of me, after all, part of the family inheritance. The only relationship that mattered to me was the one I had with alcohol.

And so I didn’t even try to moderate my habit, even when life got serious and I had a job in PR in London. ‘I can’t help it,’ I used to say as I poured yet another glass, or got up in the middle of the night to swig from a bottle under my bed, or didn’t go to work so I could stay and drink in my flat all day.

After all, I reasoned, this was how my mother coped with life. If you inherit something, you can’t help doing it, I’d tell myself; it’s all written for you in a chromosomal time bomb.

But if I could justify my behaviour as part of a genetic inheritance, others gave me far less grace. Soon, the detritus of an alcoholic life was piling up beside me: unpaid bills I couldn’t bear to open, friends who distanced themselves from me, exasperated, solemn warnings about my behaviour at work. In the middle of the night when I woke to my heart pounding, I thought I could hear voices shouting at me.

In the grey of the early morning, as I lit my first cigarette, I’d jump at the slightest sound. Aged 24, a decade after I fell in love with booze, my nervous system was shot to pieces, my eyes bloodshot and rimmed with tiredness, my hands permanently shaking.

Confused, I struggled to make sense of what was happening to me. ‘You have your whole life ahead of you!’ people told me. It didn’t feel anything like that. By the age of 25, I was so profoundly depressed, I ended up in a mental health unit and had to move back in with my mother in Oxford. There, I slept all day and drank in the evenings.

I still didn’t know that I was up against something truly deadly. My mother, still drinking and in the middle of her third marriage break-up, didn’t know what was happening to her either. And she felt helpless to help me, as I continued my descent.

Symmetries started to emerge between us. When we rose from our beds in the afternoon, we would both pass over coffee or late lunch to start drinking again straight away.

Neither of us could remember conversations that we’d had the previous day. Life was pushing us in the same direction – although it would take some time for us to arrive there.

And where was that destination? My mother got there first. But when I saw where she was, I wanted nothing to do with it.

In the spring of 2009, aged 56, she announced that she had stopped drinking. More than that, she quickly announced that she was now a member of Alcoholics Anonymous. What? My mother? Careful scepticism soon turned to derision. At heart, I felt betrayed.

So as she skipped off to daily meetings with a new group of friends, I doubled down on my drinking. I laughed at her newfound optimism as I poured myself drinks in front of her. Once, when she came into the kitchen where I was drinking with friends, I even offered her a glass of wine as a taunt.

No alcoholic likes to be shown up by the cold light of sobriety and I was no different. But if I laughed and mocked AA, it had entered my subconscious. On mornings when my hangover was too bad to do anything else, I found myself looking for the bits of AA literature she left by her bedside table.

I can’t remember my last drunk. That’s what they call it in AA. Not your last drink but the last time you got drunk. The distinction matters because typically, alcoholics drink to get drunk. No small glass of Sancerre for us. I was taken home in an ambulance the last time I got drunk. The shame of it. I do remember my last hangover the morning after; I can almost taste the bittersweet resolve to change.

And change, when it came, was unpredictable. Was my mother happy that her 26-year-old daughter was following her into the rooms of AA, just nine months after she herself had decided she wanted to get sober?

Not hugely. We laugh about that now, but she didn’t want me there with her at first. She wanted to heal and I can understand that. After a lifetime of symmetries with her daughter, she wanted to break free, to work out a jigsaw puzzle that didn’t have me as the missing piece.

It’s now been more than 15 years since I had a drink but I still haven’t pieced together my own jigsaw puzzle.

I went to my first AA meeting without Mum. Eventually, we would go to some of them together, becoming a double act of sorts – but as she spoke in these meetings, I never thought of her as ‘Mum’. Disassociating to cope, I thought of her as ‘Julia’. My life, once so barren and confusing to me, is now full: I am married with two small children. Mum tells me that seeing me model sober motherhood sometimes gives her a stab of envy, that I am achieving what she could not.

Do I worry that my girls might drink like my mother and I did before them? Sometimes.

Sometimes I get scared that I can’t outrun the past or that it will crash into the present like a boulder. My eldest daughter, now seven, asks me questions that make me sad and happy at the same time: ‘Do you drink alcohol?’ or ‘Why don’t you drink, Mummy?’

I want to answer her fully, but I check myself; is this too much for her? Are an alcoholic and a mummy incompatible terms? It is my life’s work to make sure that this isn’t the case. I believe that they are not.

Last year, Mum and I published a book about our path to join sobriety. As writers, we did the only thing we really know how to: we wrote it down.

In the pages of that book, we wrote down what happened as we saw it. We felt certain that we didn’t want to edit out parts of the book that made one or the other look bad; we wanted to keep the electricity of a real conversation between mother and daughter within the pages themselves.

When the book was published, some people told us how brave we were, others told us that we had brought shame on our family, that we had washed our family’s dirty laundry in public.

Nearly a year later, I am still emerging from the shock of exposure. But I have never felt brave. Leave the bravery to others who deserve it; I simply used my life as evidence of a problem I see all around me, every day, if only we could dare to name it.

Last week, Mum and I sat in my kitchen. We drank coffee. ‘I feel like I have failed you,’ Mum says, as we go over the hereditary nature of addiction.

As I tell her that no one has failed anyone, I catch her moving the hair away from her eyes in a way I do too.

And there it is: the shock of similarity and the pain of difference. How do come to terms with the knowledge of generational addiction?

I’m still working that out, but I no longer feel as if it is too heavy a burden to carry or something that might dirty my fingers.

Yet my life is also so much more than three for a tenner from Threshers.

• Arabella is an ambassador for Nacoa, which provides help to children affected by addiction.

In The Blood, by Julia Hamilton and Arabella Byrne (£16.99, HarperCollins) is out now