Call it an early mid-life crisis: that awful realisation, which typically hits you in your late 30s or early 40s, that you may never fulfil all your childhood dreams.

Homing in on this particular strain of existential angst is Togetherness, an HBO comedy-drama that looks at the quiet discontent of married couple Brett and Michelle (Mark Duplass and Melanie Lynskey), their friend Alex (Steve Zissis) and Michelle's sister Tina (Amanda Peet) as all four approach middle age.

The show is written by Jay Duplass, 42, and his brother Mark, 39, the independent film-making duo behind films such as The Skeleton Twins (2014) and Baghead (2008), who co-created Togetherness with their friend Zissis, 40.

Speaking to The Straits Times in Los Angeles, the cast and creators say a lot of the show's cringeworthy moments and uncomfortable truths come from their own lives and struggles with getting older.

Observing friends who are the same age, they believe there is something universal about this stage of life and the strain it can put on marriages, careers, romance and friendships.

Jay says: "We're all questioning who we have become and whether it matches up with the dreams we had when we were 16-year-olds thinking about what we wanted to be and where we did well and where we didn't and the sense of melancholy there.

"In the most intimate relationships, it can drive you together because you can share that thing and that sense of 'Oh my gosh, look what's happening, we're in mid-life, is this really who we want to be?'

"But it can also drive you apart because if you're not feeling good and not communicating, it can just cause an explosion."

This is why some married couples find it hard to watch the show, which portrays a loving relationship between Brett and Michelle, but also shows them struggling to maintain intimacy.

The Duplasses say whether you see it more as a comedy or a drama depends on how closely your own experiences mirror those of the main characters.

For example, Brett and Michelle's awkward attempts to jazz up their sex life and maintain intimacy can be funny or tragic or both.

"Married couples have a hard time watching Brett and Michelle," says Mark. "They see that storyline as a very hard-hitting drama, but single people love to laugh at us and make fun of us."

Having young children can sometimes exacerbate the panic of approaching middle age - parents around 40 like him, his brother and Peet, 44, know this all too well.

"There's a very specific thing that happens when your last baby starts sleeping," says Jay, who is married to Jennifer Tracy-Duplass and, like his brother, has two children aged about seven and three.

"You emerge from that fugue state of your child's infancy and you no longer know who you are and what your relationship with your spouse is about anymore."

"And you're really saggy," quips Peet, who is married to Game Of Thrones creator David Benioff and has three children aged one to nine. "Boobs are down to your belly button."

For women, there is the extra social and cultural baggage that comes with the physical aspects of ageing, says the actress, whose character Tina is also unhappy about being childless and single in her late 30s.

Even though she is married and a mother herself, Peet says she has no trouble relating to this.

"For a long time, I didn't know what all the hoopla was about with women being so afraid to get older, even just superficially, like getting wrinkles and the obsession with youth.

"But now I feel very stricken with horrible feelings of nostalgia and am sometimes shocked that I'm 44. Like, just shocked at the number.

"Even the choice to wear really tight clothes - I'm really angry that there are things that are not ageappropriate for me anymore. So I really do relate to Tina. The panic of facing middle age is not hard for me to relate to," she says, laughing.

The show, which is set in Los Angeles, is also inspired by the added challenge of forging and maintaining close relationships, especially while living in a large city where one has few roots.

Says Mark, who is married to actress Katie Aselton: "That is at the heart of our show, I think: the intense desire of these four people to band up in a big mega-metropolis like Los Angeles - where you feel isolated and alone - to create a sense of community and come together.

"Then you get a little bit too close and you just say, 'Get the f**k away from me, I need my space.' That thing is why we love this show."

•Togetherness Season 2 airs on HBO (StarHub TV Channel 601) on Mondays at 11.30am and 11.30pm.