30/10/2014 11:30 GMT | Updated 29/12/2014 05:59 GMT

The Dementia Crisis- It Wont Be Improved By Biasing Doctors' Advice

Right at the beginning of Jerome K Jerome's masterpiece "Three men in a boat," the hero picks up a medical dictionary and discovers that he has the symptoms of every disease mentioned with the exception of housemaid's knee. The prescription he is given surprises him. After beer, steak, exercise and early bedtimes, it ends with the words "and don't stuff up your head with things you don't understand."

Yes, most of us have been there a few times; the pain in the chest that turned out to be indigestion, the blood in the urine which followed a dish of beetroot, the other symptoms which came and then went. It is always easy to imagine the worst. Why I even heard of someone telling his doctor that he was afraid he might have a severe case of manflu, a self diagnosis which, I may say, turned out to be entirely correct. But of all the possible symptoms it must surely be those of dementia which worry us most. How did I fail to call in at the post office? How could I have forgotten the name of the last prime minister but one, or where we went on holiday or who I sat next to at dinner last week? The trouble is that the symptoms are so similar to those of normal absentmindedness and the effects of dementia are so bleak, that minor incidents of forgetfulness can lead to a frightening cycle of self diagnosis (it cannot be normal to forget things like that), self treatment (I will now learn a list of the last twenty French prime ministers) and, hopefully, relief (yes, it's much better now. My memory probably just wanted exercise).

The role of a doctor in this area is a difficult one. There are therapies which might help with the disease and he would not want his patient to miss out on these. On the other hand a mistaken belief that one is suffering from dementia can destroy someone's life. Which way will he lean? The answer is that he must not lean at all. His duty must be to use his knowledge, his experience and his common sense to give the right advice. Of course he will occasionally get it wrong in either direction. Professional men do. Nonetheless he must try his best.

It is difficult to see how the highly contentious proposal that the NHS should pay £55 pounds to every doctor who prescribes dementia can possibly square with this. The £55 is intended as an incentive. It is presumably, therefore, intended that it will affect the doctor's diagnosis. So he will no longer be giving his best advice but rather advice with a bias set by official priorities. Other professional advisers have to explain to their client if they have a conflict of interest, if they receive commission for recommending an insurance company or something of that sort. The better ones will tell the client that if they receive any commission they will pay it over to the client so that it can never be said that they were biased. So how should doctors live up to this standard under the new regime?

"I am afraid I must diagnose you as suffering from dementia. I should add that by doing so I net myself £55."

"And what would your diagnosis be if you weren't getting the £55, Doc?"

"Oh then I would say that it was normal forgetfulness."

The only thing worse than that would be if the doctor lied at this point.

One can understand why the NHS is anxious that dementia should be spotted earlier. It is a terrible scourge and as the population ages, likely to become more so. Still the answer is not to prevent doctors from giving honest advice. From a practical point of view that is self defeating since people will become even shyer of getting medical advice on the issue but the real issue goes beyond this. The public does not trust politicians but it does trust the integrity of doctors. It is probably right in both judgements. We must not allow the politicians to pull the doctors down to their level.