Too many patients diagnosed with depression when they're just down in the dumps

Professor Gordon Parker warns that the medicalisation of unhappiness has fed a booming trade in prescription drugs and ineffective treatments.

Depression has become a "catchall" diagnosis in the 21st century, driven by clever marketing, he says.

The attack in the British Medical Journal highlights growing controversy over the issue.

Using the current clinical guidelines for diagnosis, around one in five adults is thought to suffer depression during their lifetime. This costs the economy billions in treatment and lost productivity.

Professor Parker, from the school of psychiatry at the University of New South Wales, says the over-diagnosis began a quarter of a century ago.

In 1980, the guidelines for diagnosis changed to include a lower threshold for minor mood disorders. It meant the term "major depression" had cachet with clinicians and helped patients claim on their medical insurance, but also classed many more as having depression.

In his 15-year study of 242 teachers, four out of five met the criteria for major, minor or sub-clinical depression, the most minor state.

The symptoms include "feeling sad, blue or down in the dumps" for two weeks or appetite change, sleep disturbance, drop in libido and fatigue. Yet these are so ubiquitous that almost everyone has them at some point in their lives, Professor Parker writes.

"It is normal to feel depressed. A low threshold for diagnosing clinical depression risks treating normal emotional states as illness."

Antidepressants have a large share of the drug market and are being marketed beyond their "true utility in a climate of heightened expectations". And serious cases of depression could be overlooked in the crowd.

"Depression will remain a nonspecific "catch all" diagnosis until common sense prevails," he argues.

However, Professor Ian Hickle of Sydney University, also writing in the BMJ, says increased diagnosis and treatment has led to a reduction in suicides and increased productivity among those afflicted.

The stigma of being "depressed" has been reduced and the old demeaning labels of "stress" and "nervous breakdown" have been abandoned, he added.

Earlier this month Dr Hamish Meldrum, head of the British Medical Association, warned that the overmedicalisation of obesity and other conditions stopped people taking responsibility for their health.