Everyone is talking about season three of Succession along with the cringe-inducing and ridiculously dysfunctional Roy family. For those not already addicted to the show’s scathing dialogue, obscene wealth and fraught family politics, it sees four siblings intent on shredding each other to bits as they vie for their father Logan’s (played by the inimitable Brian Cox) approval, as well as his media empire, Waystar Royco.

We have scapegoat-turncoat Kendall (Jeremy Strong), snaky Shiv (Sarah Snook), obnoxious but vulnerable Roman (Kieran Culkin) and borderline delusional Connor (Alan Ruck) – and the sibling toxicity is very, very palpable.

While most of us aren’t constantly pondering the extreme lengths we’ll go to undermine and oust a sibling from the family business, it’s likely, if you didn’t grow up solo, that at one point or another, a certain amount of rivalry snuck into your sibling relationships. But when is competition healthy, and when does that contest slip into toxicity?

Is sibling rivalry healthy?

Relate Counsellor Simone Bose doesn’t believe sibling rivalry can ever really be positive. “The minute you start to feel like you’re unequal in some way, that tends to affect your self-worth in relation to the people around you,” she explains. “So I wouldn’t say it’s a very healthy thing.”

There are particular problems, she notes, if “a parent is going about trying to create competition between their children; it tends to have more of a negative impact”. She says there are parents who do behave in this way, and it’s certainly Logan’s modus operandi in Succession, where he repeatedly manipulates and pits his children against one another. Such behaviour, says Bose, “creates a lot of anxiety, mental health issues, low self esteem”.

“Naturally, children fight for and need their parents’ love, and they need to feel safe,” she continues, “and if they don’t feel safe, that impacts their self-worth, and it affects their stress levels. And that gets wired in at a very young age, and it can impact them into adulthood.”

Are there any benefits to having a reasonable amount of sibling competition?

“In terms of learning how to share, learning how to accept when you don’t win something, for instance, [how] not to be a sore loser, that type of thing, I think that’s healthy,” considers Bose. “Because in life, you need to be prepared for the fact you’re not always going to win; you’re not always going to be the one that’s so special all the time. But I think that’s as far as it would probably go.”

What are the signs a rivalry is becoming toxic or damaging?

There are signs to watch out for in children that might suggest sibling rivalry is becoming an issue. Bose says a child may start to behave differently, may put themselves down, behave aggressively or resentfully, act out, or show they’re trying to be perfect, or fulfil a certain role within the family.

This idea of trying to fulfil a role can carry on into adulthood, says Bose. “Even if you’re the ‘favourite’, you might always feel like you have to be perfect, and there’s high expectations on you, which can also be very stressful for a child and for an adult,” she explains. “Having to be on the ball all the time, otherwise [you can feel] you’re not worth anything, you’re a failure, you’re nothing, and you’re not lovable, you’re not acceptable to your parent.”

It works both ways too; if you don’t consider yourself the ‘favourite’ child or sibling, that can lead back to low self-esteem, doubt in yourself, and negative self talk.

How does sibling rivalry work in adulthood?

Bose says she’s found in her work as a therapist, that people often return to, and reflect on, the roles they played as children, and their position amongst their siblings. “You’ll find that one was always the one that took care of the mother; one was always the naughty one; one was always the one that wasn’t taken seriously… you get these different roles and they can build resentments.”

That, she says, can contribute to a break down in sibling relationships as adults. “Even though you’re all adults, you can still be playing that child role.”

What you can do to avoid toxic sibling rivalry?

The key to avoiding a toxic situation between yourself and your siblings, and with your parents, says Bose, is to address it. “You’ve got to work on not repeating [behaviours] and work on your relationships with your siblings.”

Eliminating blame may be difficult, but it’s good to remember that even if you perceive one sibling to be the ‘favourite’ and your rival, it’s not their fault. “And even if they play up to it sometimes, it’s because ultimately, the child in us always wants to be loved by our parents,” says Bose. “We do the things we do to try and get that love.”

Bose suggests therapy, which can help you “work on learning how to love yourself and reparent yourself in a way that’s healthy”. She also encourages not looking to your parents so much as an adult, “because you’re not a child anymore” and being compassionate towards yourself.

If it is really toxic, then thinking, ‘I need a bit more separation’ can also be valuable, she adds, as can trying to understand your siblings and where they come from. “It’s not their fault. They’re also a product of their upbringing.”

Succession is available to watch on Sky and Nov TV