My father is single-handedly chopping down a tree, and simultaneously building a pergola. He's multi-tasking; running races with his children; furiously whisking vinaigrette. My mother recognises the danger signs. "Oh dear," she says, mildly, "your father's forgotten to take his hectic pills." Later that night there will be sobbing hysteria. He will beat his head against the wall over and over before driving off into the night threatening suicide.