Everyone was in favour of the SNRIs, though. Everyone but Isolde. She’s like our mother was: too thin and proud of it, tall, chainsmoking, glamorous. She’s a fashion photographer. She said – it’s not an illness, Luce. Crying. Screaming. Being a smartarse. Saying no for no good reason. It’s called a personality.

I don’t see Isolde very often now. Last time Andrew and I had dinner with her, she told him he dressed like the kind of man who hangs around primary schools. Later, when Andrew asked about her superannuation, Isolde said nothing, just popped her knuckles one by one.

When we were children, Isolde and I used to fight over my grandmother’s wedding dress. Whoever wore it was the queen; the other had to play a variety of roles: dog, princess, king, jester, knight. The dress came into my possession because the other thing we fought over, my mother’s engagement ring with the central diamond missing, belongs to Isolde now. She wears it on a chain around her neck.

In your brain – this is how the doctor had put it to me – when something happens to make you feel good, you release a chemical. It’s released by one neuron – he drew a circle – travels along the synapse – he added a curved line – and is absorbed back into another neuron, like this. He made a gesture, a bird’s talons closing around its prey. The Serotonin and Norepinephrine Reuptake Inhibitors, he said, prevent a neuron taking the serotonin back, so it stays circulating in your brain. See?

And that will make me happy? I asked.

No, not happy, not exactly, he said. It will even you out.

How often, now, when I’m at work, do I think of this phrase. I am evened out as I giftwrap the gold and cream and black embossed boxes. I am evened out helping men choose how their girlfriend or mistress or wife should smell. I am evened out when I talk to women about the idea of a signature scent, the one perfume that will help them be remembered.

It was my mother who taught me about perfume, about the families into which fragrances arrange themselves: floral and chypre, woody and oriental; she taught me about vetiver and tuberose, oakmoss and tobacco, orange blossom, rose, violet, aldehydes, musk. She once did what I do now, except that she worked in a small boutique whose owners were French, and who taught her how to complain about customers in a language they wouldn’t understand. When Isolde and I were little, she taught us the words they used to say: Salope. Putain. Connard. And when a customer left without buying anything: Va te faire foutre, whispered under the breath.