Thursday, 6 December 2012

Icebergs and Onions

It is a mantra of medical and social science reports that when cases of a new disorder are found, they are described as being “only the tip of the iceberg”.  Autism, alcoholism, child sexual abuse, drug abuse, diabetes, dyslexia, high cholesterol, high blood pressure, hyperactivity, and post-traumatic stress disorder are examples of conditions which are frequently described in this way. There may be several hundred others. According to the iceberg analogy there is a lot of illness and misery out there. This search for the afflicted (the iceberg beneath water level) may be motivated by altruistic concern for others or it might be a cynical ploy to drum up business for drug companies and purveyors of therapy.

Some under-counting is understandable. Many conditions are not nice to admit to, and are best denied. Some are illegal. Few people willingly admit to a stain on their character, a permanent flaw in their fundamental nature. Further, many citizens have been living their lives under the misapprehension that they were normal, and do not take kindly to being labelled in any way. They do not wish to be accused of having spoken prose all their lives.

Some over-counting is understandable. If the new diagnosis is about a transitory and treatable difficulty due to outside causes, it can become fashionable, with celebrity sufferers recruiting fellow victims and forming lobbying groups. As Lady Bracknell observed in The Importance of being Ernest:  “None of us are perfect. I myself am peculiarly susceptible to draughts”.  Confessing to a minor diagnosis can be cool. To say “I am illiterate” is not a career boosting move. The attribution is inner and permanent. To ask “How good are your facilities for registered dyslexics?” has a much better ring to it. The narrative has moved from a personal failing to a social requirement to provide for a specific and legitimate handicap.

How can we obtain accurate numbers?

We cannot find out until we ask the question. There are so many questions to be asked in psychology and medicine that a selection must be made, and some will be left out. This makes sense because some conditions are much commoner than others. Special interest groups argue for the inclusion of particular lines of enquiry and this usually leads to a higher rate of reported of cases, which confirms the “tip of the iceberg” theory.  If a doctor or psychologist has been on a training course, they will begin to diagnose more of those sorts of cases, sometimes correctly, often incorrectly. So, we cannot find until we look, yet once we are on the lookout we may see cases where none exist.

Autism is a good example. This severe condition exists. Accurate diagnosis depends on training and experience, and there are well-established indicators and measures of severity. Unfortunately, what was once a narrow diagnostic category has entered popular culture as meaning anyone who is not particularly social and is a little too interested in technical matters.  For those who fail to get the autism diagnosis, Asperger’s syndrome may be seen as a consolation prize. By the way, these syndromes are not laughing matters, but the search for diagnostic labels is a two-edged sword.  The sufferer may get the reassuring legitimacy provided by a diagnostic authority and gain resources from government agencies, but might possibly be blocked from being treated normally and thus exacerbate and prolong their difficulties.

There are powerful forces moving us toward the proliferation of diagnosed disorders. One of the few growth stories in our moribund economy is provided by The Diagnostic and Statistical Manual of Mental Disorders. When launched in 1968 it contained 182 disorders. By 1980 it had reached 265, by 1994 there were 297 and the next revision out soon will very probably raise that number.  To the cynical eye, DSM is a child of the US health insurance industry: no patient can be repaid their medical bills unless the doctor writes down a diagnostic number. No number, no cash. So, the all difficulties of life must be numbered, and the greater the number of diagnoses the greater the opportunities for therapists of all types. The iceberg tendency is in the ascendant.

Layers of an onion

If you peel away all the layers of the onion, it ceases to exist. None of the layers are the onion itself, yet no onion is left without them. So it is with the endless reclassifications of normal reactions as disorders.  The person is slowly reduced by a set of dissociative classifications.  They become “person-with”: person with diabetes, person-with memory problems, person-with anger management issues.  Given a large enough armamentarium of diagnoses, normality ceases to exist.

One can do some rough calculations based on the prevalence of diagnosed disorders. The World Health Organization reported in 2001 that one in four people meet criteria for some form of mental disorder or brain condition at some point in their life. Believe that if you will, though of course life time estimates could include one short episode in an otherwise untroubled life.  Here are the ranges given for the prevalence of each condition in 14 countries: anxiety 2.4 to 18.2%, mood disorders 0.8 to 9.6%, substance abuse 0.1 to 6.4%, impulse-control disorders 0 to 6.8. The authors are of the iceberg tendency, and believe that their figures are under-estimates. Clearly, some countries have not come into line with the putative Central Classification System, and don’t realise quite how miserable and disordered people are.

If we repeat the procedure for physical health, we would have to discount those who were too fat, too thin, all those with chronic conditions, and perhaps those who are being medicated because they may be thought to be at risk. For example, giving statins those who are healthy but have high cholesterol (of the bad sort), which is at best an indicator, and not a disease itself. It would be easy to show that at least 25% of the population were unhealthy at some time in their lives and probably chronically unhealthy for the last third of their lives.

Putting together the mentally disordered and the physically unwell results in a small core of citizens being classified as “well”, and even then, perhaps a more detailed enquiry could turn up hidden problems. Peeling away the onion transforms normality into layers of syndromes for which invoices can be issued. The classificatory project has colonial ambitions, and a whole industry behind it.

Can order be brought to this chaos?

Contemporary psychiatry and psychology believe they have the antidote to hand. They restrict diagnostic categories to a set of well-defined indicators which have to achieve set levels of severity and duration. In sober hands, such defined disorders can be diagnosed in a responsible fashion.

Questionnaires can be a help. Patients are more likely to admit to drinking too much and to having served time in prison when confessing to a piece of paper rather than a psychiatrist. It is a commonplace of clinical psychology interviews that if one wants to ask about drug abuse it is easier to hand the patient a list of drugs and ask casually “which of these have you used”? The list begins with pain-killers and antibiotics, and goes on to harder stuff. A bit of distance aids confession.

However, humans are tricky. They deny bad characteristics, complain loudly about aches and pains when sympathy or compensation are offered, and contradict themselves when the mood takes them. They look up diagnoses on the internet, and learn the answers to interview questions.

Why not treat them like fish in the sea, and net and tag them? Put a net into the sea, pull out the fish and tag each one with a shiny Time 1 tag. Then, a few weeks later, visit the same area and repeat the process, tagging each fish with a Time 2 tag. While doing this you will catch a few fish with a Time 1 tag already on them. Note the number of such fish. It you really want to be accurate, repeat the process a third time.

Charming as it might be for psychologists to become fishers of men, members of the public are likely to object to being tagged in the name of science. We cannot use nets or tranquiliser darts. However, a name is a tag. Most places we go, we leave a name. Checking names does the trick. For example, how many drug users are there in North London? The Police have one estimate, based on a list of arrests. The Courts have another list of names. The General Practitioners have their own lists of registered addicts. Each of those lists is a net, which tags every person.

Capture-recapture methodologies come to the rescue here.  The Lincoln-Petersen method, in the interests of simplicity shown here for only two nettings is:

N= (M C) / R
N = Estimate of total population size
M = Total number of animals captured and marked on the first visit
C = Total number of animals captured on the second visit
R = Number of animals captured on the first visit that were then recaptured on the second visit

So, let us estimate the number of hard drug users in a defined neighbourhood.  The Police have a list of names of people they have arrested, and 10 of those live in the neighbourhood. The local drug clinic has a list of names of users and 15 of those live in the neighbourhood. Five of those 15 are also on the Police list, so they have been “re-captured”.

N= (M C) / R = (10 x 15) / 5 = 30

In this example, the Lincoln–Petersen method estimates that there are 30 drug users in the neighbourhood.

Perhaps we have to turn away from self-proclaimed claims of disorder and get out our nets. Using our nametags instead of nets and physical tags, we have to check for the overlap of names in different lists, and then do our calculations. Sure, we can give citizens questionnaires about their sexual behaviour, but it might be better to check names on Sexually Transmitted Disease Clinics to get more reliable estimates, and to calibrate the questionnaire replies. Given access to the data, by tracing every purchase and every location visited, every bill paid or ignored, every credit card transaction and every health clinic attendance, every TV program watched we will finally find out, with considerable reliability, who we are, and what mental state we are in.

So, when the next new mental disorder is described in the media, always ask yourself: is this the tip of the iceberg or the skin of an onion? 

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