Taylor Swift sings about 'eldest daughter syndrome', but is it real?

When Jess King heard the term "eldest daughter syndrome", she immediately felt "seen".

"I first heard about it on TikTok … I just fit that mould to a tee," says the curve model and influencer from Melbourne/Naarm.

"I'm high-achieving, a perfectionist.

"Growing up, you always felt like you had to go that extra mile to kind of stand out and to be recognised."

While not a diagnosable condition, according to experts, eldest daughter syndrome is having a moment after global music superstar Taylor Swift wrote about the "terminal uniqueness" in her latest album.

"Here is someone who's managed to articulate it so beautifully, it's quite validating," Jess says.

"You feel as if you're heard and recognised."

Eldest daughter syndrome has been described by researchers as a psychological and social phenomenon where firstborn daughters can have unequal responsibilities within their families.

Clinical psychologist Kim Stirling from Brisbane/Meanjin told ABC's Radio National Life Matters program the concept has a deep history in both Eastern and Western cultures.

"That expectation [historically] in a family system for the eldest daughter to take on those caregiving duties and higher levels of responsibility within the family."

"Particularly in families where there might be resource shortages or higher parental workload, especially for more rural families or larger family systems.

"That eldest daughter tends to take on that role of extra mum in the family system."

She says it is "interesting" that modern society is now identifying the concept and finding it relevant.

"It's not a clinical diagnosis, we're really just looking at a cluster of traits that are pretty common among eldest daughters," she says.

These traits can include:

"They tend to be more independent and self-reliant," Dr Stirling says.

"That's stemming from that fear they're going to be a burden on the family system if they're taking up too much resource for themselves."

Dr Rachael Sharman, a university lecturer in clinical psychology on the Sunshine Coast/Kabi Kabi lands, says some people may relate to the term but feel indifferent to it.

"To be fair, some people are quite happy to be the eldest daughter," she says.

"You're often very organised, self-reliant and independent.

"For some people it kind of suits their personality, they're happy with being the family organiser."

Dr Stirling says for others, the deeply held beliefs and conditioning can have longer-term impacts.

"The biggest thing I would see in clinical practice is that they're going to be self-sacrificing and suppressing their own needs again for fear of being a burden," Dr Stirling says.

"So that's going to impact the way they're interacting with the world around them and their relationships in their adult life."

Jess says she often felt like she had to be the "responsible one" and the person everyone in her family relied on.

"Now, as an adult, I can see how that sense of always needing to take care of things has stuck with me," she says.

"I have diagnosed anxiety that affects me daily, and I'm always worried that I'm not doing enough or that I'll let someone down.