‘We argue about such trivial things as moving items around in the fridge.’ Photograph: Kevin Kozicki/Getty Images/Image Source

My elder sister and I were extremely close when we were younger (we are very near in age) and, while we bickered as teenagers, we remained firm friends. Now we are adults in our 20s, that has all changed, and I fear that we have irrevocably lost what we once had. I would love to get it back.

We moved around different cities after university, but ended up in the same city, hardly seeing each other. Now, through a quirk of timing in tenancy agreements, we are back living together.

You wouldn’t know we are sisters from the way we interact at home – we seem more like strangers. When she is not out, she is very insular and considers an evening (or day) alone in her room with the door shut, time well spent. I thrive, and am dependent on company to invigorate me, and resent that she doesn’t care to constantly interact with me. She needs time on her own regularly, and as I am not this sort of person, this is something I simply won’t understand.

Our differing food habits are also a big source of frustration. She eats the same meal every day and never cooks, which I find sad. She will occasionally join me if I cook dinner, but the favour is never returned. I long for the sort of houseshare where people take it in turns to cook so there is always something nice to eat when you get home, and where people spend their evenings chatting over dinner and maybe watching TV together – but this never happens. It especially upsets me that she doesn’t join in if I have friends round.

Her controlled personality can also lead to her being very controlling of me. We have had serious arguments about such trivial things as her asking me to stop singing – I refused because it is my home, too, and it makes me happy – and moving items around in the fridge to fit things in, which she doesn’t like if it affects anything of hers.

I am finding it hard to come to terms with just how different we have become in adulthood. I find her to be too rigid and controlled, a bit of a snob and a health obsessive, while I’m sure she thinks that I am irrational and over-emotional, and too dependent on others. I am upset that we have lost our natural connection, and I would like to be able to repair it while we still live together.

There seems to be this feeling that, because you are sisters, you should be similar and do many things together. Maybe this was the case when you were children, but you don’t seem to have separated out from your childhood personas. And siblings are rarely similar, even if they are genetically close.

I consulted Peter Wilson, a psychotherapist (childpsychotherapy.org.uk). The first thing he said was: “I can’t understand why you are living with each other.” I think this is exacerbating everything because it is forcing you and your differences together. When all you can see are differences, there seems to be no common ground on which to build, when, in fact, there can be with a bit of perspective and negotiation.

What Wilson also helped me to understand is that, in adolescence, even children who got on before can find themselves diverging. “Everybody’s adolescence is very different,” he explains, “and it is then that people tune in to their own individual personalities. It’s when we start to discover who we are.” In other words, all those things that tie us together with family can go through immense change in adolescence as we form our own identities and we can move apart from those with whom we grew up.

It doesn’t mean your relationship with your sister is over. Your 20s can be a decade of great change and finding yourself. You may discover that you reunite in a few years’ time. But one thing is certain, the way you are going about things now is not conducive to that happening.

Read back over what you said and imagine it the other way around: “My sister wants me to constantly spend time with her and eat dinner with her, and when she invites friends over she wants me to be with her. She won’t stop singing even though I have asked her …” You call her controlling, but you sound very controlling of her (See? You do have some things in common!).

I wondered where your rather idealised view of a sisterly relationship came from. Where are your parents? Has something happened to make you cling to your sister so?

“It’s important,” counsels Wilson, “to recognise your differences. Your sister may be in a different place. Look at where you are in your life and where else you can get that companionship.”

I understand places to live aren’t easy to find, but you need to separate out and find your own place, or step back from trying to make your sister be all things to you. Sibling relationships go through many incarnations. As with any relationship, let this one breathe, don’t define yourself through it and invest in the many other friendships you seem to have.

I was also struck by something: when you describe what you want, it sounds very much like a home environment – you may get that in a few years, but it probably won’t be your sister who provides it.

To the reader who wrote to me this week on coloured paper: please contact the National Domestic Violence helpline, 0808 2000 247 (womensaid.org.uk), to discuss your next safe move. If you fear your life is in immediate danger call 999.

Your problems solved

Contact Annalisa Barbieri, The Guardian, Kings Place, 90 York Way, London N1 9GU, or email annalisa.barbieri@mac.com. Annalisa regrets she cannot enter into personal correspondence.