Leaving the Young Vic studio after Anamaria Marinca’s astounding 72-minute performance of Sarah Kane’s 4.48 Psychosis is like letting go of a breath that has been held for too long. All of Kane’s play are intense of course, but director Christian Benedetti’s decision to present 4.48 Psychosis as a one-woman show heightens this intensity to the extent that everything else is swallowed up in it.

This play, Kane’s last before she killed herself, presents the inner workings of a psychotic mind, the thoughts and feelings of a person who has made the decision to end her life as a cure for the misery of existence. Discussions with doctors, mad ramblings and rational explanations of suicidal impulses are all delivered with utter commitment by Marinca, whose Eastern European accent (she is Romanian) gives an almost robotic tone to Kane’s words.

For the duration of the piece Marinca is glued to the stage, her feet not budging one inch from where stands when the lights first go up on her. She is not, however, still. The residual tension from this lack of movement is poured into her gaze, voice and upper body, so that the performance remains intensely physical, every movement emphasised.

Kane’s text seeks to draw our attention to difficult issues such as self-harm, depression and the failure of the medical establishment to fully engage with those suffering from mental health problems, but all this is presented in such a way that the audience cannot help but become overwhelmed. A few brief moments of dark humour relieve the gloom, but we are never really given access to the character put before us.

The one-woman format (previous interpretations have used larger casts) leads inevitably to the assumption that the play we are watching is autobiographical, but this is not necessarily the case and does the production no favours. Presented with the idea that the character before us is Kane herself it is tempting to regard the themes being discussed as purely personal and thereby fail to full engage with their universality.

Furthermore, so much concentration is required to engage with the intensity of Marinca’s extremely impressive performance that it is easy to become distracted from the emotional and psychological states that inform it.

Benedetti and Marinca, along with lighting designer Dominique Fortin, whose simple design is highly effective at focusing our attention at crucial moments, have a produced a work of great achievement here. What is uncertain however is whether the play at its heart is quite worth it.