However familiar it had become, she was still irritated by the phrase ‘missing heritability’, implying that genetic connections might turn up one day, like a favourite family cat, if only enough posters were put in shop windows or stuck on neighbourhood trees. For something to be ‘missing’ it had to have been there in the first place, but as far as the experiments showed, the correspondences were mostly non-existent, and only got upgraded to ‘missing’ by a doctrinaire refusal to revise the original hypothesis. It was a phrase from the same semantic playbook as ‘side effect’, which tried to pretend that among the range of pharmaceutical effects caused by a medicine the undesirable ones were somehow incidental. A patient suffering from blindness or liver failure after taking a medicine might well find the experience just as central as the intended effect. Would a depressive who had spent years feeling cursed by having the less active version of the SLC6A4 gene feel that she was on a ‘potentially valuable’ path when its connection with depression turned out to be ‘missing’ and that she had been waiting for a cure that could not exist, while losing out on those that did? As the daughter of two psychoanalysts, and the sister of a clinical psychologist, Olivia was especially pissed off that so much money had been spent and so many papers had been written pretending that this ‘candidate gene’ was the cause of depression; money that could have been spent on helping depressed people – for instance – or mending potholes.