ANGUS HOWARTH

DOCTORS are over-diagnosing depression, resulting in thousands of people wrongly being prescribed drugs to treat it, an expert warns today.

Professor Gordon Parker says the current threshold for what is considered to be “clinical depression” is too low and he fears that it might lead to the condition becoming less credible. He argues that the problem has been reduced to the “absurd” and we risk medicalising normal human distress and viewing any expression of depression as necessary of treatment.

Prof Parker, a psychiatrist based at Australia’s University of New South Wales, says it is “normal to be depressed” and points to his own cohort study, which followed 242 teachers. After 15 years of research, 79 per cent of respondents had already met the symptom and duration criteria for major, minor or very mild “subsyndromal” depression.

Anti-depressants have a range of side-effects. About 25 per cent of patients have problems when stopping them and studies have found that they can cause a rise in suicidal thoughts and actions. Patients also report a loss of libido.

Prof Parker blames the over-diagnosis of clinical depression on a change in its categorisation, in 1980, which saw the condition split into “major” and “minor” disorders. He says that the simplicity and gravitas of “major depression” gave it credit with clinicians, while its descriptive profile set a low threshold.

Criterion A required a person to be in a “dysphoric mood” for two weeks, which included feeling “down in the dumps”. Criterion B involved appetite change, sleep disturbance, drop in libido and fatigue. This model was then extended to include what Prof Parker describes as a seeming subliminal condition, “subsyndromal depression”.

Writing in the British Medical Journal, Prof Parker said: “It is normal to feel depressed. A low threshold for diagnosing clinical depression risks treating normal emotional states as illness.

“Now, anti-depressant drugs have a large share of the drug market. Reasons for the over- diagnosis include lack of a reliable diagnostic model and marketing of treatments beyond their true utility in a climate of heightened expectations.

“That many people with substantive clinical depression do not have their condition diagnosed does not mean that depression is under-diagnosed.” He added: “Depression will remain a non-specific ‘catch all’ diagnosis until commonsense prevails.”

Last year, a group of charities, including the Mental Health Foundation and Mind, called for a “large, sustained cash injection to improve psychological treatments”.

A recent study in the United States found that as many as one-quarter of people currently labelled as depressed were reacting normally to stressful events. It suggested that even psychiatrists regularly miss the broad picture. Some experts say that once patients tick enough boxes for symptoms, then they get diagnosed as depressed even though they may just be sad.

However, Dr Andrew McCulloch, chief executive of the Mental Health Foundation, said: “It is very unlikely that depression is over-diagnosed in the UK. Vast numbers never seek help: they will struggle; some enough to take their own lives.” But he added: “A GP ought to be able to offer a range of treatments, including counselling and exercise, not just medication. Medication is relied upon heavily in the UK by GPs and patients and is often prescribed when an alternative might have been more suitable.”

Last updated: 16-Aug-07 00:09 BST