Electric shock therapy - or electro-convulsive therapy - divides opinion and causes much heated debate. It is a treatment whereby a small, measured, electric current is passed through the brain, administered under anaesthetic. Some patients report real benefits from ECT; others find it unpleasant and upsetting with no noticeable improvement. Many experts argue that the most effective way of treating depression is a combination of drugs and ECT, while others insist that talking therapies are the real solution.

Part of the fear of electric shock therapy is probably the fear of electricity itself and the fact that the equipment, certainly in its earlier forms, looks like a torturing device. There's also the matter of "not being sure how or why it works, but that it seems to", and the side-effects, which can include loss of memory - usually short-term - and burnt or stinging patches of skin.

The idea for ECT came from Italian psychiatrist Ugo Cerletti in 1938, and it is in late 1939 that the story of Rowan the Strange begins. The setting is wartime England and, following periods of disturbing behaviour - culminating in his breaking a number of his sister Laurel's fingers when slamming down a piano lid - Ro (the Rowan of the title) is sent to a lunatic asylum in Kent. Just 13 years old, he finds himself in a ward with, initially, just one other patient: Dorothea. They are the test subjects of Dr von Metzer, a caring and compassionate man who has high hopes for ECT.

Ro is a big fan of the new Superman comics and, somewhere along the way, has convinced himself that his parents aren't really his parents and that he has super-powers. The feisty Dorothea, meanwhile, claims that everyone has an angel - hers being Joan of Arc - that only she can see. A strong, believable and ultimately tragic character, Dorothea is a superb creation.

Julie Hearn is extremely even-handed in her presentation of the treatment, and of Dr von Metzer - a flawed but ultimately good man who has the additional burden of being a German in England when England is at war with Germany. (Von Metzer later discovers the culpability of many doctors and scientists in the atrocities being carried out in the Fatherland, adding to his inner turmoil.)

Other characters include the asylum's director, who wants quick results and a quiet life; Nurse Springfield the nursing assistant, whom Ro has a crush on at the outset but whom Dorothea always refers to as "little Miss Clacton-on-Sea"; and Nurse Bradley, who has written her own pantomime version of Peter Pan for the staff and a few (carefully selected) "low-risks" to perform.

Much of the action revolves around preparations for Peter Pan in what is a multi-layered, interwoven plot. Against his will, Von Metzer, already seen by some staff as "the enemy", is forced to play the role of the evil Captain Hook. When Ro and some of his fellow patients are taken on a trip to the cinema to see the latest film, however, the entire story can be seen in a new light: such is Hearn's skill as a writer.

Some members of Ro's family will be familiar to readers of Hearn's earlier works; he is the son of Hazel and grandson of Ivy, both of whom have title roles in previous books, but Rowan the Strange works perfectly as a strangely beautiful stand-alone story. It is nothing short of extraordinary.

Philip Ardagh's Stinking Rich and Just Plain Stinky and The Year that It Rained Cows are published by Faber.