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2.5 The definition of depression

The new, intensive focus on depression as a widespread disease has been underpinned by the work of nosologists, specialists in classifying and defining illness. The foremost definitions of depression are those developed by panels of experts convened by the American Psychiatric Association. The APA’s Diagnostic and Statistical Manual was first compiled in 1952 to assist the national census of mental disability, but has since been transformed. The fourth edition, known as DSM-IV, was published in 1994 and is now internationally recognised as the prime definition of how to recognise depression and, implicitly, when and how to treat it. DSM-IV definitions are also closely linked to those in the WHO’s International Classification of Diseases (ICD-10) and arguably now drive them.

DSM-IV is in some sense a great achievement, each new edition representing decades of development and years of expert work. The task is formidable and very costly: establishing the ground rules demands feats of understanding, organisation and painstaking application, and great political skill would have been needed to secure anything like consensus and general acceptance. And clearly the need for good definition is paramount. It is fundamental to common understandings, good communication and effective diagnosis; lack of definition increases the risk of wishful, misguided thinking and unhelpful treatment and practice.

However, what matters it is how useful the definitions are and to what effect on health - and this depends on many different pluses and minuses, with much judgement needed about which is which. If DSM-IV were a fishing net, the question would be: what mesh size should be used to catch depressed fish but not others ? The mesh has been getting smaller over the years, but it this a good or bad thing ?

Number of 'diagnostic entities' in DSM

Edition Date Number
DSM-I 1952 106
DSM-II 1968 182
DSM-III 1980 265
DSM-IIIR 1987 392
DSM-IV 1994 307

Five editions of the DSM have produced a threefold increase in "disease entities". What Hippocrates knew as melancholy is now identifiable in 300 manifestations (including manic depression), detectable through the expression of many commonplace symptoms and characterised by often familiar behaviours. But how much does this explain ill-health and help doctors to relieve suffering, and has the time come for "National Depression Screening Days" (1997) to be extended beyond the US?

Perhaps the DSM classification offers convenient rather than convincing solutions and has rationalised rather than reduced diagnostic chaos. Perhaps longer definitions make less sense, by directing towards a circumference of blurry understandings, the more they elaborate the central point. In expanding definitions of "depression", perhaps these guidelines have helped to promote something like hypochondriasis (DSM-IV, F45.2) as well:

"If people are educated to believe they are fundamentally fragile, always on the verge of mortal disease, perpetually in need of health-care professionals at every side, always dependent on an imagined discipline of ‘preventive’ medicine, there can be no limit to the numbers of doctors’ offices, clinics, and hospitals required to meet the demand ... We are, in real life, a reasonably healthy people. Far from being ineptly put together, we are amazingly tough, durable organisms, full of health, ready for most contingencies. The new danger to our well-being, if we continue to listen to all the talk, is in becoming a nation of healthy hypochondriacs, living gingerly, worrying ourselves half to death" (Thomas, 1979)

In authenticating more and more diagnoses, the DSM process has helped to legitimise a dramatic increase in drug use (the dominant treatment mode) for conditions that become wider and wider in scope. That might be a risk with elaborate definitions, especially when "diagnoses are made by counting symptoms, preferably those that are easily observable, and those that are easily agreed upon by direct questioning of the patient". (Van Praag, 1996) What kind of symptoms may signal a "major depressive episode", for example ? The explanatory memorandum in DSM-IV brings to mind small mesh and a wide net:

"The mood in a Major Depressive Episode is often described by the person as depressed, sad, hopeless, discouraged, or ‘down in the dumps’ (Criterion A1). In some cases, sadness may be denied at first, but may subsequently be elicited by interview (eg by pointing out that the individual looks as if he or she is about to cry). In some individuals who complain of feeling ‘blah,’ having no feelings or feeling anxious, the presence of a depressed mood can be inferred from the person’s facial expression and demeanour. Some individuals emphasise somatic complaints (eg bodily aches and pains) rather than reporting feelings of sadness. Many individuals report or exhibit increased irritability ..."

A2 "Loss of interest or pleasure is nearly always present, at least to some degree. Individuals may report feeling less interested in hobbies ... (eg a former avid golfer no longer plays, a child who used to enjoy soccer finds excuses not to practice)."

A3 "Appetite is usually reduced ... (but) other individuals ... may have increased appetite ... (and) there may be a significant loss or gain in weight."

A4 The most common sleep disturbance associated with a Major Depressive Episode is insomnia" (including "middle insomnia ... terminal insomnia" ...and "initial insomnia") and "less frequently, individuals present with oversleeping (hypersomnia) ... Sometimes the reason that the individual seeks treatment is for the disturbed sleep"

A5 "Psychomotor changes include agitation (eg the inability to sit still ...) ... or retardation (eg slowed speech, thinking or body movements ...)."

A6 "Decreased energy, tiredness and fatigue are common ..."

A7 "The sense of worthlessness or guilt associated with a major Depressive Episode may include unrealistic negative evaluations of one’s worth or guilty preoccupations or ruminations over minor past failings."

A8 "Many individuals report impaired ability to think, concentrate or make decisions ... They may appear easily distracted or complain of memory difficulties.

Importantly, the last of the identifiers (Criterion A9) suggests that "Frequently, there may be thoughts of death, suicidal ideation, or suicide attempts". But it is not a necessary condition for the diagnosis, and in other depressive states (eg "Depressive Disorder Not Otherwise Specified") may not feature at all.

A formal diagnosis for Major Depressive Episode can be met by two conditions. One relates to the severity and duration of the depressed state, though these might be inferred simply by reason of the patient going to the doctor. In addition to depressed mood, the patient should also have at least four ticks in the remaining eight boxes (A2 to A9).

To this extent, the currency of "depression" has become debased over the years, and this colours the question: "Do antidepressants work ?" Nowadays, perhaps the most unifying definition of "depression" is that it is a condition to be treated with antidepressant drugs. There may not be a lot to distinguish between the drugs, but there is no end of possibilities for prescribing them. The trend in definition has been to identify more and more people as "depressed", to extend the patient base:

"The boundaries of what constitutes depression have been expanded relentlessly outward. Depression as a major psychiatric illness involving bleakness of mood, self-loathing, an inability to experience pleasure and suicidal thoughts has been familiar for many centuries. The illness has a heavy biological component. Depression in the vocabulary of post 1960s American psychiatry has become tantamount to dysphoria, meaning unhappiness, in combination with loss of appetite and difficulty sleeping". (Shorter, 1997)

The way in which depression is now formally defined has expanded the market also by effectively undermining a major instrument of regulatory control. When drugs are licensed, by law they can be promoted only for quite strictly defined indications - but as antidepressants have typically been indicated "for the treatment of symptoms of depressive disease", DSM-IV provides scope for great over-simplification. This is exemplified in the following, the complete text of a full-page advertisement for the leading SSRI: (Lilly, 1993)


First line ... for all nine symptoms of depression

Depressed mood Loss of interest Fatigue
Sleep disturbances Weight/appetite change Lack of concentration
Slowness/ restlessness Guilt/feelings of worthlessness Thoughts of death

Prozac, fluoxetine hydrochloride."


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