Routine

Joy worries constantly about filling her time, repeatedly asking:

What will I do while I’m lasting, Marianne, what will I do?

Trying to wait out her depression, she survives by recording events and making lists of things to be done. She refers to a checklist that Marianne has left her, which suggests activities to keep her busy in the evening - listen to the radio, watch tv, have a bath etc

At the beginning of the novel she takes comfort in daily routine:

just getting on with the day to day til it got less terrible.

And later on, while in hospital, she still realises how important regular habits are:

I like routines. You can get cosy in a rut. You can pretend things are the same when they're not.

Joy is uncertain of herself and who she is supposed to be. Her attempts at cooking and baking suggest she is trying to fill the traditional female role of homemaker, much as Ellen does. But she has no-one to make food for. And she looks to define her identity and purpose through work. She refers to her job as a drama teacher:

This is where I earn my definition, the place that tells me what I am.

Similarly her position in the betting shop provides a focus and distraction at weekends. Joy is unable to hold herself together, to live with lies in these roles. As a result she is absent more and more frequently. She finally takes leave of absence from her teaching job and admits herself into a psychiatric hospital.