Sir, - In his article on depression, Dr Muiris Houston presents a viewpoint favoured by most doctors, but one which is highly suspect (Health, December 17th).
He writes that, in his view, "depression is no different from diabetes. In one you take insulin and in the other you take Prozac or some other antidepressant. Both substances are simply designed to replace natural chemicals missing from the body."
This simplistic, persuasively-presented argument presents the public with a logic which seems to make perfect sense, amply justifying the widespread use of anti-depressant medication by GPs and psychiatrists. Yet even a cursory examination of the facts demonstrates that the analogy is highly suspect.
Diabetes is characterised by a raised blood sugar, caused by a deficiency of insulin. No doctor would dream of diagnosing it without first checking the blood sugar level. The guidelines for diagnosing diabetes are well established, based on internationally accepted blood sugar levels. The ongoing treatment of diabetes is carefully monitored by regular blood sugar level tests to ensure that the patient is on the right amount of insulin.
This well-established clinical approach to diabetes contrasts sharply with the medical approach to depression. Unlike diabetes, in which a deficiency of insulin is well established, no chemical abnormality has been reliably identified in depression. Contrary to popular opinion, fuelled principaly by the medical profession and the pharmaceutical industry, it has not been established that depression is caused by low levels of serotonin in the brain. This is because doctors have no way of checking blood or brain serotonin levels. Hence, they have no solid scientific grounds upon which to compare diabetes and depression. Yet doctors do so frequently.
Since people diagnosed as having depression never have their supposed biochemical abnormality checked by blood or other tests, the only logical conclusion is that doctors are - on a massive scale - basing their diagnosis of a supposed serotonin deficiency on an act of faith.
Indeed, not even when a doctor decides to stop the antidepressant can he/she check the brain or blood levels of serotonin. The decisions to start, continue, and stop antidepressants are all undertaken without any reference to blood or other tests. This is a far cry from the precision involved in the medical treatment of diabetes.
To illustrate further the woolliness of the medical approach to depression, take the scenario which evolves when a doctor decides to stop antidepressants after six to nine months. Diabetic patients receiving insulin need it for the rest of their lives. It cannot be stopped after six to nine months, or the biochemical problem (high blood sugar) will always resurface. In depression, what has happened to the supposed biochemical abnormality? Has it corrected itself? Was it ever there? How can anyone know, when no tests are carried out at any stage of the process?
Elsewhere, Dr Houston describes the reaction of one man to the Vincent Browne radio programme, a man who felt marginalised by the discussion on depression and mental illness. I can understand that many people may have been shocked to hear that no biochemical abnormality has been identified for any psychiatric condition, particularly those who have been told by doctors that their condition is caused by a known biochemical deficiency. There may have been many issues raised on that programme which were news - and therefore shocking - to many listeners. But they were the truth, and I note that Dr Houston stops short of suggesting that any views expressed on that programme were untruths. On that programme I fully acknowledged that some people feel better on antidepressants, because antidepressants are mood-altering drugs. A commonly unrecognised reason why people feel worse when antidepressants are stopped is that they may be experiencing a withdrawal reaction, that their system is missing the drug which it has become used to. To suggest, as many doctors do, that antidepressants work by correcting biochemical brain imbalances is in my opinion misleading: it is an aspirational hypothesis which currently has not been proven.
I agree with Dr Houston that evangelical approaches should always be considered with caution. This certainly applies to the evangelical approach of the vast majority of GPs and psychiatrists to antidepressants, based, as it is, on faith rather than on science. That the medical profession is prepared to make such unsubstantiated comparisons between diabetes and depression is, in my opinion, indicative of a need for a public inquiry into mental health, and mental health care. - Yours, etc.,
Dr Terry Lynch, (Author of Beyond Prozac: Healing Mental Suffering Without Drugs), Russell Court, Ballykeefe, Limerick