The form Laing has invented mixes literary criticism and poetic reverie, travel reportage and confessional autobiography, and the fit is sometimes awkward. Casual conversations with fellow travellers pass the time but often have dubious relevance; her itinerary can seem – as she says of Scott Fitzgerald's jerky essay about his alcoholic crack-up – "circuitous and rambling". The subtitle promises a general answer to a question that the book avoids directly asking. Doesn't the creative imagination always require external help – from a deity or a muse as classical poets believed, or from the animating breeze exhaled by nature, on which romantic poets relied? Coleridge needed opium, and Aldous Huxley recommended a hallucinogenic cactus. Is writing itself addictive, a disease not a cure?

Despite its haphazard structure, The Trip to Echo Spring is original, brave and very moving. Laing's way of looking at a natural world that is free from human faults repeatedly prompts something like the "spiritual awakening" AA attendees hope for. Her insights shine with beauty yet are shaded by sympathy and compassion, as when she notices in passing a herd of deer with "faces soft and unguarded as sleepwalkers". Her recommended therapy, for drunks and for everyone else who suffers, is "the capacity of literature to somehow salve a sense of soreness, to make one feel less flinchingly alone". The self-destructive subjects in her clinic testify to that; so does her own writing.