I Know This Much Is True, Sky Atlantic review - riding a carousel of catastrophe

Adapted by writer-director Derek Cianfrance from Wally Lamb’s 1998 novel, this HBO production (on Sky Atlantic) presents a huge canvas for Mark Ruffalo, who plays the twin brothers Dominick and Thomas Birdsey.

He had a particular interest in I Know This Much Is True, since his own brother was murdered in Los Angeles in 2008. If nothing else he deserves accolades for sheer fortitude. Thomas is a paranoid schizophrenic who suffers increasingly traumatic episodes, while Dominick’s life is lived in the shadow of his brother’s illness and what it costs him to try to protect him.

The depths of Thomas’s illness are revealed early on, when he chops off his own hand in the library of the brothers’ home town, Three Rivers, Connecticut. Apparently he wanted to make a protest about the Gulf War (it’s 1990). Doctors want to reattach the hand, but Thomas is adamant that they must not. Dominick, asked to give his permission for the medics to go ahead, agonises over it but ultimately decides that Thomas’s decision must stand.

It’s a stark, if lurid, illustration of the challenges, choices and burdens imposed by mental illness, and as the story develops we see how the brothers’ relationship has been moulded by the constant battle to accommodate Thomas’s condition. It’s in episode two that Dominick will meet therapist Dr Rubina Patel (Archie Panjabi, pictured below), who throws revealing light on his interdependency with Thomas, while Dominick is battling to extract his brother from the grim high-security facility to which he has been forcibly dragged by the unfeeling authorities.

You might say the twins were born under a bad sign, and powerful as it is, I Know This Much… too often resembles a crushing and remorseless catalogue of woes, the kind of terrible fate the Greek gods on Mount Olympus were wont to hurl down on those who had displeased them. As if the pivotal theme of mental illness were not enough, we see how ancestral karma has blighted the twins’ lives. They suffered the loss of their mother to breast cancer, while the mystery of their true father’s identity, a topic their mother always refused to discuss, is another cloud looming over their heads. Their stepfather, Ray (John Procaccino), seems like a bitter and angry loser, though you’ll have to wait a while before his own particular murky story is unravelled. There’s also rape, a cot death, suicide and a car accident to look forward to.

With its hardscrabble storylines and dimly-lit north-east US locations, I Know This Much… is sometimes reminiscent of the likes of Kenneth Lonergan’s You Can Count On Me (which also starred Ruffalo) or Manchester by the Sea, though compressing Lamb’s 900-page doorstep-crusher into six episodes probably accounts for the sense that you’re trapped on a whirling carousel of catastrophe with the controls stuck on Fast. There is, nevertheless, a glimmer of light at the end of the ride, if you can stick with it.

• More TV reviews on theartsdesk