Last night's television: More attention to detail, please

HORIZON: LIVING WITH ADHD BBC2; THE REAL DA VINCI CODE C4

You don't have to strain hard to detect irony in the idea of a TV programme about Attention Deficit Hyperactivity Disorder. So many programmes these days are made on the assumption that ADHD is what most viewers suffer from. Last night's Horizon on the subject began with an intriguing promise that it would take "a different approach". But "different" in the case of Horizon - a series that, for all its faults, tends to be interested in evidence and experiment - turned out to mean doing what every other TV series would have done. In other words, "Living with ADHD" threw out the science and went straight for the human interest.

The film followed two families. First up was Liam, a boy with an unnerving affinity for busy roads and the parapets of multi-storey car parks. His parents' attempts to shout him out of these preferences were useless, though, since he also suffered from "Oppositional Defiant Disorder", medical parlance for "being an awkward little bastard". Then came Jasmine and James, whose fighting and swearing made life hell for their mother, Charlotte, who was, it emerged, a comparatively rare case of adult ADHD.

All three children, it was clear, were extremely naughty, and naughtiness is gripping. The sequence in which James locked himself in the laundry room and lost the key down the back of the freezer was a real and affecting drama. But it was hard to see from the tantrums what propelled their naughtiness into the realms of the medical. The commentary talked confidently about ADHD as a "neurological" disorder - implicating some physical process in the brain - but we didn't get a proper account of what this process might be.

And how could the physiological be disentangled from the psychological in these stories? It can't have been beside the point that Liam had a baby sister - for any firstborn, the harbinger of another sort of attention deficit. At one point, Charlotte mentioned positive feedback and boosted self-esteem as things that helped Jasmine and James control their behaviour. It was hard to see the neurological basis of this. In her own case, Charlotte was inclined to treat her past history of severe cocaine abuse as an effect of her ADHD rather than a cause of it.

None of this is to say that ADHD is a fictitious condition, or that what these three children needed was a clip round the ear. But if Horizon didn't even bother raising such questions, let alone trying to answer them, what was the point of it?

Next to this, the scepticism of The Real Da Vinci Code was very welcome. Not having read Dan Brown's bestseller, I hadn't grasped that it is another contribution to the grand corpus of Holy Grail conspiracy theories, which revolve around the idea that Jesus Christ was married to Mary Magdalene, and that their bloodline is guarded by the mysterious Priory of the Order of Sion. Tony Robinson weeded out the nonsense, revealing that the Order of Sion was largely invented by Gerard de Sede, a member of Oulipo, the Workshop of Potential Literature. In other words, it is a literary prank, to be classified with Georges Perec's novel that excludes the letter E.

The Real Da Vinci Code had two problems. Firstly, at two hours, it dragged on far longer than the subject warranted. The second was a slackness of language that had Robinson talking about, for example, an 800-year-old "theory" that the Grail was the cup used at the Last Supper. Since the Grail is, he established, a medieval fiction, you can't have theories about it (is it a theory that Hamlet was prince of Denmark?). Still, it was a blow struck for rationality against conspiracy theorists. Not that they ever notice.