What is a mental illness?

  There is a marked circularity about this (‘a psychiatrist is someone who diagnoses and treats psychiatric disorders’, ‘psychiatric disorders are those conditions which are diagnosed and treated by psychiatrists’). There has been endless controversy about the reliability of psychiatric diagnoses and even whether or not mental illnesses exist at all (Chapter 5). It is worth spending a little time on why psychiatric diagnoses are so controversial both because it keeps cropping up and also because the same issues are fundamental to all medicine although rarely as striking.

The subjectivity of diagnosis

  The hallmark of the psychiatrist’s trade is the interview. We make our diagnoses (and still conduct much of our treatment) in face-to-face discussions with patients. We take a careful history (as do all doctors) but then, instead of, or sometimes in addition to, conducting a physical examination (feeling the abdomen, taking the pulse, listening through a stethoscope) we conduct what is called a ‘mental state exam’. In this we probe deeper into what is worrying the patient, their mood, way of thinking, etc. Some of this involves simply noting what the patient reports (that they are hearing strange sounds or that they panic every time they think of going out) but some involves us in constructing an understanding of what they are going through using ‘directed empathy’. Directed empathy means actively putting ourselves in their shoes, understanding what they are feeling and thinking, even if they have difficulty in expressing it. For instance we may come to the conclusion that a patient who recounts a series of vindictive acts carried out against them by strangers and friends alike is, in fact, excessively suspicious (paranoid) leading to misinterpretation of common events.

  This ability to piece together how other people experience things and what they are feeling is an essential human capacity. Understanding how others see the world from their perspective (often called having ‘a theory of mind’) is so important that its absence, as in Autism or Asperger’s Syndrome, is a profound handicap. Psychiatrists train up this skill and, because of increasing familiarity with the range of disorders, can use it actively to understand the confused and confusing experiences that patients recount to them.

  Diagnoses based on a patient’s mental state contain no concrete evidence for the diagnosis – there are no blood tests or x-ray pictures. A written list of what is said or a detailed description of the behaviour (e.g. the diagnostic criteria for depression) are only part of the process. Psychiatric diagnoses rely on making a judgement about why someone is doing something, not just the observation of what they are doing. Hence the criticism that they are not scientific; they are not ‘objective’. Take the example of an elderly man who is profoundly depressed. He may not say that he is depressed but instead complain of tiredness, aches and pains, poor sleep and feelings of guilt. As he deteriorates he may lie unmoving all day or even not speak at all. A psychiatrist will probably interpret his immobility as a feature of depression. In doing this (usually supported by the other clues) he hypothesizes that the immobility is a result of despair and hopelessness. There are lots of other possible causes of immobility (or ‘stupor’ in its most extreme form) and the psychiatrist distinguishes depressive stupor from those caused by hormonal or neurological problems by building up a picture of the patient’s mental state, i.e. why he is not moving or communicating.